| Filter Interfaces | Microsoft DirectShow Interfaces:IAMAnalogVideoDecoder, IAMCameraControl,IAMDroppedFrames, IAMVideoProcAmp,IBaseFilter, IKsPropertySet, ISpecifyPropertyPagesCapture Interfaces:IGOChip, IGOChipConfig, IGOInfo, IAccess-Func, IAdvanced |
| Video Capture Pin Supported Media Types | DIVX_MPEG4, MICROSOFT_MPEG4,MPEG2, MPEG1, H263, MJPG |
| Video Capture Pin Interfaces | Microsoft DirectShow Interfaces:IAMStreamConfig, IKsPin, IKsPropertySet, IPin |
| Video Preview Pin Supported Media Types | DIVX_MPEG4, MICROSOFT_MPEG4,MPEG2, MPEG1, H263, MJPG |
| Video Preview Pin Interfaces | Microsoft DirectShow Interfaces:IAMStreamConfig, IKsPin, IKsPropertySet, IPin |
| Audio Capture Pin Supported Media Types | MEDIATYPE_Audio, MEDIASUBTYPE_PCM,MEDIASUBTYPE_ADPCM,MEDIASUBTYPE_IMA_ADPCM |
| Audio Capture Pin Interfaces | Microsoft DirectShow Interfaces:IAMBufferNegotiation, IAMStreamConfig, IAMStreamControl, IKsPin, IKsPropertySet, IStreamBuilder, IMediaSeeking, IPin,IQualityControl |
| Filter CLSID | Not applicable. |
| Property Page CLSID | Video Control Property Page:35D3656A-6C20-46B0-B44A-DC8E861F1205Audio Control Property Page:8ED37ED7-477B-4764-B72E-DFC2D1899C6C |
| Merit | MERIT_DO_NOT_USE |
| Filter Category | AM_KSCATEGORY_CAPTURECLSID_VideoInputDeviceCategoryCLSID_AudioInputDeviceCategory |
Table 2-3: WDM Streaming Capture Filter
For Microsoft DirectShow interfaces, follow the links for online reference. Alternatively, please visit http://msdn.microsoft.com/library/ and from the left panel navigation, select Graphics and Multimedia -> DirectX -> SDK Documentation -> DirectX 9.0 (C++) -> DirectShow -> DirectShow Reference -> Interfaces for a complete list of Microsoft DirectShow filter interfaces references.
Media Types
DIVX\_MPEG4
| Category | Section | Function |
| System | 3.4 | Mpg24_PreviewOpen(CardNo) |
| Mpg24_PreviewClose(CardNo) |
| Mpg24_EncoderOpen(CardNo, PortNo) |
| Mpg24_EncoderClose(CardNo, PortNo) |
| Mpg24_PlayFileClose(Index) |
| Mpg24_ReadSerial(CardNo, HighByte, LowByte) |
| Configuration | 3.5 | Mpg24_PreviewGetImageRange(CardNo, Property, Min, Max, SteppingDelta, Default) |
| Mpg24_PreviewSetImageConfig(CardNo, Property, Value) |
| Mpg24_PreviewGetImageConfig(CardNo, Property, Value) |
| Mpg24_PreviewSetVideoFormat(CardNo, FormatIndex, Value) |
| Mpg24_PreviewGetVideoFormat(CardNo, FormatIndex, Value) |
| Mpg24_PreviewSetDisplay(CardNo, Handle, X, Y, AutoShow) |
| Mpg24_PreviewSetCustomSize(CardNo, Width, Height) |
| Mpg24_EncoderGetImageRange(CardNo, PortNo, Property, Min, Max, SteppingDelta, Default) |
| Mpg24_EncoderSetImageConfig(CardNo, PortNo, Property, Value) |
| Mpg24_EncoderGetImageConfig(CardNo, PortNoProperty, Value) |
| Mpg24_EncoderSetVideoFormat(CardNo, PortNo, FormatIndex, Value) |
| Mpg24_EncoderGetVideoFormat(CardNo, PortNo, FormatIndex, Value) |
| Mpg24_EncoderSetFile(CardNo, PortNo, FileName) |
| Mpg24_PlayFileSetFile(Index, FileName) |
| Mpg24_PlayFileSetDisplay(Index, Handle, X, Y, Width, Height, AutoShow) |
| Action | 3.6 | Mpg24_PreviewRun(CardNo) |
| Mpg24_PreviewPause(CardNo) |
| Mpg24_PreviewStop(CardNo) |
| Mpg24_PreviewSavelmage(CardNo, FileName) |
| Mpg24_PreviewSelectChannel(CardNo, PortNo, Mode) |
| Mpg24_PreviewShow(CardNo, Visible) |
| Mpg24_EncoderSetOSD(CardNo, PortNo, OSDText, Len) |
| Mpg24_EncoderRun(CardNo, PortNo) |
| Mpg24_EncoderStop(CardNo, PortNo) |
| Mpg24_PlayFileRun(Index) |
| Mpg24_PlayFilePause(Index) |
| Mpg24_PlayFileStop(Index) |
| Mpg24_PlayFileShow(Index, Visible) |
| Mpg24_PlayFileSavelmage(Index, FileName) |
| Watchdog | 3.7 | Mpg24_WatchdogConfig(CardNo, TriggerInterval) |
| Mpg24_WatchdogEnable(CardNo) |
| Mpg24_WatchdogDisable(CardNo) |
| Mpg24_WatchdogTrigger(CardNo) |
| IO | 3.8 | Mpg24_SetGPIO(CardNo, PortNo, Status) |
| Mpg24_GetGPIO(CardNo, PortNo, Status) |
| Mpg24_WriteEEPROM(CardNo, Offset, Value) |
| Mpg24_ReadEEPROM(CardNo, Offset, Value) |
| Misc. | 3.9 | Mpg24_PreviewCallback(CardNo, CallbackProc) |
| Mpg24_PreviewGetStatus(CardNo, Status) |
| Mpg24_EncoderCallback(CardNo, PortNo, CallbackProc) |
| Mpg24_EncoderGetStatus(CardNo, PortNo, Status) |
| Mpg24_PlayFileCallback(Index, CallbackProc) |
| Mpg24_PlayFileGetStatus(Index, Status) |
| Mpg24_GetLastErrorInfo(ErrorInfo) |
# 3.3 Setting Up the Build Environment
# Include Files
All applications using the APIs need include the file shown the following table.
| Method | Description |
| Initialization Operation Method |
| CreateInstance | Create an instance for this interface. |
| Release | Release the instance for this interface. |
| DeviceExist | Specify if a device is present |
| GetBoardInfo | Get board information |
| Video Operation Method |
| SetVideoConfig | Set the video config. The setting will not take effect until next call of StartCapturing. |
| StartCapturing | start capturing video from chip using the pre-set stream and bitrate setting |
| StopCapturing | Stop capturing |
| GetOneFrame | Get one video frame from chip, this function works in block mode, it will not return until a frame is unavailable or StopCapturing is called. |
| SetVideoSource | Set video input source. |
| GetVideoSource | Get video input source. |
| SetTVStandard | Specify TV standard. |
| ChangePFrameRate | Change frame rate only for P frame. |
| SetFPS | Set frame rate for I, P and B frame. |
| BitrateControl | Specify bitrate of the output video. |
| SetResolution | Specify the output video stream resolution. |
| ChangeIFrameQuantizer | Change quantized scale only for I frame. |
| ChangePFrameQuantizer | Change quantized scale only for P frame. |
| ChangeBrightness | Specify brightness value of output video. |
| ChangeContrast | Specify contrast value of output video. |
| ChangeHue | Specify hue value of output video. |
| ChangeSaturation | Specify saturation value of output video. |
| ForceIFrame | Insert an Iframe. |
| InsertNewSequenceHeader | Insert a new sequence header. |
| sigDetect | Monitor signal lost |
| SetMDRegions | Set motion detection region. |
| SetMDThresholdsAndSensitivities | Set threshold and sensitivity value for motion detection |
| ResetMotionDetection | Reset motion detection. |
| InitMotionDetection | Initialize motion detection |
| osd_show | Show osd |
| Debugging Operation Method |
| ReadCBusReg | Read from c-bus registers for debugging. |
| WriteCBusReg | Write to c-bus registers for debugging. |
| ReadCBus | Read from c-bus register |
| WriteCBus | Write data to c-bus register |
| I2C_WriteRegister | Write peripheral chip registers via I2C bus |
| GPIO_Read | Read the status of GPIO pins. |
# Initialization Methods
# CreateInstance
# Synopsis:
STATIC SINT32 CreateInstance (VOID \*\*pp, SINT8 instance)
# Description:
This function creates an instance for CVideoCapture interface.
# Arguments:
VOID \*\*pp – [out] Pointer to this new instance. It should be allocated memory by the caller.
SINT8 instance – [in] Index number of the connected device. The range should be from 0 to the return value of GetDeviceNumber () - 1.
# Returns:
SINT32 – Status of whether the new instance is created successfully.
SUCCESS (0x0000) – success;
ERR\_MEMORY (0x0002) – no enough memory to create a new instance;
ERR\_DEVICE (0x0001) – device file can not be opened.
# Notes:
The argument, pp, is checked to ensure that it is not NULL. If yes, ERR\_MEMORY will be returned.
# Release
# Synopsis:
VOID Release ()
# Description:
This function releases the instance of CVideoCapture interface. And it also frees its allocated memory.
# Arguments:
None
# Returns:
None
# DeviceExist
# Synopsis:
SINT32 DeviceExist ()
# Description:
This function specifies if a device is present.
# Arguments:
None
# Returns:
SINT32 – Status of whether the device exists.
0 – device not exists
1 – device exists
# GetBoardInfo
# Synopsis:
void GetBoardInfo (REVISION\_INFO \*p\_bi)
# Description:
This function gets the encoder information.
# Arguments:
REVISION\_INFO \*p\_bi - [out] A pointer to board information, caller is responsible to allocate memory for it.
# Returns:
None
# Video Operation Methods
# SetVideoConfig
# Synopsis:
void SetVideoConfig (TCFGVIDEO \*pcfgvideo)
# Description:
This function sets the video configuration but not take effect immediately until next call of StartCapturing ().
# Arguments:
TCFGVIDEO \*pcfgvideo – [in] A pointer to an instance of structure TCFGVIDEO. The caller should allocate memory for it.
# Returns:
None
# Notes:
This setting will not take effect until next call of StartCapturing.
# StartCapturing
# Synopsis:
SINT32 StartCapturing ()
# Description:
This function starts capturing video from chip using the pre-set stream and bit rate setting.
# Arguments:
None
# Returns:
SINT32 – status of whether video capture starts successfully
SUCCESS (0) – success
ERR\_DEVICE (0x0001) – device initialization failed.
# Notes:
The function configures audio and video with pre-set value. The device will be put into DS\_RUNNING status if start successfully.
# StopCapturing
# Synopsis:
SINT32 StopCapturing ()
# Description:
This function stops capturing.
# Arguments:
None
# Returns:
SINT32 – status of if capture stops successfully
SUCCESS (0) – device stops successfully
ERR\_DEVICE (0x0001) – chip is not in running state
# GetOneFrame
# Synopsis:
SINT32 GetOneFrame (UINT8 \*pBuf, SINT32 BufLen, TFrameInfo \*pFI)
# Description:
This function gets one video frame from chip and stores into pBuf.
# Arguments:
UINT8 \*pBuf – [out] Buffer for receiving the video stream, caller is responsible for allocating a buffer big enough.
SINT32 BufLen – [in] Buffer length, caller is responsible for setting a valid buffer length.
TFrameInfo \*pFI – [out] A pointer to TFrameInfo structure, it will save the returned frame information; caller is responsible for allocating memory for it.
# Returns:
SINT32 – status of if get one frame successfully
SUCCESS (0) – get one frame from chip successfully
ERR\_DEVICE (0x0001) – device not open or chip is not in running state ERR\_NOMOREFRAME (0x1000) – no more frame is available in chip.
# Notes:
This function works in block mode, it will not return until a frame is unavailable or StopCapturing () is called. If return ERR\_NOMOREFRAME, StopCapturing () is called.
# SetVideoSource
# Synopsis:
SINT32 SetVideoSource (SINT32 source)
# Description:
This function set the input video source.
# Arguments:
SINT32 source – [in] input video source: 1 for Composite and 0 for S-Video
# Returns:
SINT32 – status of video source setting:
0 - success
-1 – error input source
# Notes:
This function will check the validity of input source. The input source is one of SVideo and Composite; if invalid it does nothing.
# GetVideoSource
# Synopsis:
SINT32 GetVideoSource (void)
# Description:
This function gets the current video input source.
# Arguments:
None
# Returns:
SINT32 – the input video source retrieved from board module.
1 – Composite
0 - SVideo
-3 – Unknown
# SetTVStandard
# Synopsis:
SINT32 SetTVStandard (UINT32 mask)
# Description:
This function specifies TV standard.
# Arguments:
UINT32 mask – [in] the TV standard: PAL and NTSC.
# Returns:
SINT32 – status of whether TV standard set successfully
0 – set TV standard successfully
-1 – no match configuration or argument error
-3 - error of unknown register
# ChangePFrameRate
# Synopsis:
SINT32 ChangePFrameRate (UINT16 rate)
# Description:
This function changes P frame rate.
# Arguments:
UINT16 rate – [in] the frame rate value.
# Returns:
SINT32 -status of this function.
0 – P Frame rate set successfully
1 – write interrupt of ON CHIP Mode is timeout
100 – MAXUSBPOLLING, write interrupt error
# SetFPS
# Synopsis:
SINT32 SetFPS (SINT32 fps)
# Description:
This function specifies frame rate for output video.
# Arguments:
SINT32 fps – [in] frame rate, the range of this value depend on the TV standard: NTSC: 30, 15, 10, 7, 6, 5, 4, 3, 2, 1;
PAL: 25, 12.5, 6.25, 5, 4, 3, 2, 1
# Returns:
SINT32 – return the frame rate value just setting.
# Notes:
This function changes frame rate in effect by quickly resetting and restarting the encoder.
# BitrateControl
# Synopsis:
SINT32 BitrateControl (SINT32 change\_direction,
SINT32 new\_i\_qscale,
SINT32 new\_p\_qscale,
SINT32 new\_target\_bitrate,
SINT32 new\_peak\_rate,
SINT32 new\_vbv\_buffer,
SINT32 new\_converge\_speed,
SINT32 new\_lambda)
# Description:
This function controls bit rate.
# Arguments:
SINT32 change\_direction – [in] the data direction when switching encode mode. This value is one of:
0: switching from VBR to VBR;
1: switching from CBR to VBR;
2: switching from VBR to CBR;
3: switching from CBR to CBR.
SINT32 new\_i\_qscale - [in] The quantized scale for I-frames. The range of this value is from 2 to 31.
SINT32 new\_p\_qscale – [in] The quantized scale for P-frames. The range of this value is from 2 to 31.
SINT32 new\_target\_bitrate - [in] The target bite rate of the encoded stream. The range of this value is from 0 to 0x1000000.
SINT32 new\_peak\_rate - [in] The peak bite rate in the encoded stream. The range of this value is from 0 to 0x4000000.
SINT32 new\_vbv\_buffer – [in] The vbv buffer size. The range of this value is from 0 to 112\*16\*1024(1835008)
SINT32 new\_converge\_speed - [in] The converge speed for CBR. The range of this value is from 0 to 100.
SINT32 new\_lambda - [in] The lambda for CBR. The range of this value is from 0 to 100.
# Returns:
SINT32 – status of if bit rate set successfully.
0 – change bit rate successfully and update the TCFGBRCTRL structure.
1 – write interrupt time out
-1 - change\_direction parameter error
-2 - new\_i\_qscale parameter out of range
-3 - new\_p\_qscale parameter out of range
-4 – new\_target\_bitrate parameter out of range
-5 – new\_peak\_rate parameter out of range
-6 – new\_converge\_speed parameter out of range
-7 - new\_lambda parameter out of range
-8 - new\_vbv\_buffer parameter out of range
# Notes:
new\_target\_bitrate parameter is the desired average target bit rate of the encoded stream, in bits per second (bps):
0: If Q>0, apply variable bit rate control (VBR) using the value of Q. If Q=0, no bit rate control algorithm is applied. Bit rate will be determined by values of IQ, PQ, BQ provided by user.
>0: Apply constant bit rate control (CBR) using the value of target\_bitrate.
new\_peak\_rate parameter is the highest bit rate allowed in the encoded stream, in bits per second (bps). This parameter is only valid when applying constant bit rate control. The larger this value is, the higher the peak bit rate is.
new\_vbv\_buffer parameter is a hypothetical decoder that is conceptually connected to the output of the encoder. Its purpose is to provide a constraint on the variability of the data rate that an encoder or editing process may produce.
For new\_converge\_speed parameter, the larger value means faster converging speed.
new\_lambda parameter is the factor determining stream quality. The larger the value is, the smoother the stream will be, but the quality of each frame will decrease. The smaller the value is, the better each picture quality in the stream will be, but the entire video stream will look jumpy due to frame drop.
# SetResolution
Synopsis:
void SetResolution (TCFGVIDEO \*pcfgvideo)
# Description:
This function specifies the output video stream resolution mode.
# Arguments:
TCFGVIDEO \*pcfgvideo – [in] A pointer to structure TCF-GVIDEO presenting one of the following mode: D1, D.5, 4SIF, 2SIF, SIF, CIF-N, CIF-P, QCIF.
Caller is responsible to allocate memory for it.
# Returns:
None
# Notes:
This function changes resolution parameters by quickly resetting and restarting the encoder.
# ChangelFrameQuantizer
# Synopsis:
SINT32 ChangeIFrameQuantizer (UINT16 iqscale)
# Description:
This function changes quantized scale for I frame.
# Arguments:
UINT16 iqscale – [in] the quantized scale value, the range of value is from 2 to 30.
# Returns:
SINT32 –status of this function:
0 – I Frame quantizer set successfully or board information can not be identified
1 – write interrupt of ON CHIP Mode is timeout
100 – MAXUSBPOLLING, write interrupt error
# Notes:
Note that higher the iqscale value, lower the image quality and lower the bit rate.
# ChangePFrameQuantizer
# Synopsis:
SINT32 ChangePFrameQuantizer (UINT16 pqscale)
# Description:
This function changes quantized scale for P frame.
# Arguments:
UINT16 iqscale – [in] the quantized scale value, the range of value is from 2 to 30.
# Returns:
SINT32 –status of this function:
0 – P Frame quantizer set successfully or board information can not be identified
1 – write interrupt of ON CHIP Mode is timeout
100 – MAXUSBPOLLING, write interrupt error
# Notes:
Note that higher the iqscale value, lower the image quality and lower the bit rate.
# ChangeBrightness
# Synopsis:
SINT32 ChangeBrightness (SINT32 brightness\_value)
# Description:
This function configures video brightness.
# Arguments:
SINT32 brightness\_value - [in] brightness value. The range of this value is from 0 to 100. Greater value means brighter.
# Returns:
SINT32 - return the input brightness value.
# Notes:
This function validates input value and if it is invalid, function does nothing.
# ChangeContrast
# Synopsis:
SINT32 ChangeContrast (SINT32 contrast\_value)
# Description:
This function configures video contrast.
# Arguments:
SINT32 contrast\_value - [in] contrast value, the range of this value is from 0 to 100. Greater value means higher the contrast.
# Returns:
SINT32 – return the input contrast value.
# Notes:
This function validates input and if it is invalid, it does nothing.
# ChangeHue
# Synopsis:
SINT32 ChangeHue (SINT32 hue\_value)
# Description:
This function configures video hue.
# Arguments:
SINT32 hue\_value - [in] hue value, the range of this value is from -50 to 50. Greater value means higher hue.
# Returns:
SINT32 – return the input hue value.
# Notes:
This function validates input and if it is invalid, function does nothing.
# ChangeSaturation
# Synopsis:
SINT32 ChangeSaturation (SINT32 saturation\_value)
# Description:
This function configures video saturation.
# Arguments:
SITN32 saturation\_value – [in] saturation value. The range of this value is from 0 to 100. Greater value means higher saturation.
# Returns:
SINT32 – return the input saturation value.
# Notes:
This function valididates input and if it is invalid, function does nothing.
# ForcelFrame
# Synopsis:
SINT32 ForceIFrame (void)
# Description:
This function inserts an Iframe into the encoded video stream.
# Arguments:
None.
# Returns:
SINT32 – status of this function:
0 – force lframe successfully or board information can not be identified
1 – write interrupt of ON CHIP Mode time out
100 – MAXUSBPOLLING, write interrupt error
InsertNewSequenceHeader
# Synopsis:
SINT32 InsertNewSequenceHeader (void)
# Description:
This function inserts a new sequence header at next GOP.
# Arguments:
None
# Returns:
SINT32 –status of this function:
0 – force a new sequence head successfully or board information can not be identified
1 – write interrupt of ON CHIP Mode is timeout
100 – MAXUSBPOLLING, write interrupt error
# sigDetect
# Synopsis:
SINT32 sigDetect (void)
# Description:
This function checks if the input signal is lost.
# Arguments:
None
# Returns:
SINT32 – status of the input signal
0 – signal lost is detected
1 – no signal lost is detected
-3 - I2C read fails
# SetMDRegions Synopsis:
SINT32 SetMDRegions (UINT8 \*arru8MotionCoordinates,
UINT32 u32MaxXCoord,
UINT32 u32MaxYCoord)
# Description:
This function set the region numbers for every macro block to watch for motion.
# Arguments:
UINT8 \*arru8MotionCoordinates – [in] Two dimensional array of region numbers where each [x][y] location contains the region number for that macro block. This argument MUST be exactly the same number of macro blocks as the current picture. If there is a size mismatch the results are undetermined.
UINT32 u32MaxXCoord – [in] The maximum X coordinate for the picture size. This is really just used for error checking.
UINT32 u32MaxYCoord – [in] The maximum Y coordinate for the picture size. This is really just used for error checking.
# Returns:
SINT32 – whether the macro block map successfully
0 - SUCCESS, the macro block map has been set in the device.
1 – ERR\_DEVICE, the macro block map had invalid regions or there was a mismatch in the picture size.
# Notes:
Be careful that this array is the same size as the picture (in macro blocks) and that the caller has initialized every location in this array to ensure that the map is correctly set.
# SetMDThresholdsAndSensitivities
# Synopsis:
SINT32 SetMDThresholdsAndSensitivities (UINT16 arrs16MotionThresholds
[MAX\_REGIONS\_OF\_INTEREST][NUM\_MOTION\_TYPES],
UINT8 \*arru8MotionSensitivity)
# Description:
Set the motion vector and SAD (Sum of Absolute Differences) thresholds for each region. Also set the sensitivity thresholds for each region.
# Arguments:
UINT16 arrs16MotionThresholds – [in] two dimensional array of thresholds of thresholds for the device.
UINT8 \*arru8MotionSensitivity – [in] one dimensional array of sensitivities.
# Returns:
SINT32 – status of if thresholds have been set successfully:
0 – SUCCESS, the macro block thresholds have been set in the device. 1 – ERR\_DEVICE, the macro block thresholds are invalid.
# Notes:
This function validates threshold input and returns ERR\_DEVICE for invalid.
# ResetMotionDetection
# Synopsis:
SINT32 ResetMotionDetection (void)
# Description:
This function reset the state array of motion detection.
# Arguments:
None
# Returns:
SINT32 – return 0 always
# InitMotionDetection
# Synopsis:
SINT32 InitMotionDetection (void)
# Description:
This function is to initialize and enable the motion detector. It is to be called before the initial package is generated as it only affects the initial package.
# Arguments:
None
# Returns:
SINT32 – return 0 always.
# Notes:
Call this before Pacgen. If you don't call this, you can't use motion detection.
# OSD\_show
# Synopsis:
SINT32 osd\_show(unsigned char x, unsigned char y, void \*String)
# Description:
This function shows osd information with the IO\_OSD\_DISPLAY IO command.
# Arguments:
unsigned char x - [in] type of osd operation:
0 – clean OSD display with writing the OSD frame EOF to the start address of current frame buffer;
1 – prepare OSD data from user to OSD buffer with OSD string format.
2 – write the prepared OSD data from the OSD buffer to firmware and display on screen.
Unsigned char y – [in] the string number of OSD data; User can input multi string to OSD buffer with the total length of OSD\_STRING\_LEN\_MAX-3.
Void \*string – [in] in order to show osd correctly, user should pass a pointer to osd\_string\_t struct, define in Include/osd.h.
x: the x coordinate of the location to show osd; in the unit of MB\_SIZE (16 pixels)
y: the y coordinate of the location to show osd in the unit of MB\_SIZE (16 pixels);
osd\_string[]: the content of string text. The max lenght is OSD\_STRING\_LEN\_MAX -3
# Returns:
SINT32 – return 0 always.
# Debugging Operation Methods
# ReadCBusReg
# Synopsis:
int ReadCBusReg (SINT32 RegNum,UINT16 Addr[],UINT16 Data[ ])
# Description:
This function reads several encoder chip registers through firmware for debugging.
# Arguments:
SINT32 RegNum – [in] Register number to identify the buffer length for register address and register data.
UINT16 Addr[ ] - [in] Array of address where read registers, caller is responsible for allocating buffer big enough.
UINT16 Data[ ] – [out] Array of data read from register, caller is responsible for allocating buffer big enough.
# Returns:
int – status of if read register successfully.
0 - success
1 – download buffer error
2 - check interrupt pipe error
# Notes:
Address and data are all in 16 bits.
# WriteCBusReg
# Synopsis:
int WriteCBusReg (SINT32 RegNum, UINT16 AddrData[])
# Description:
This function writes data to a register on the C-bus for debugging.
# Arguments:
SINT32 RegNum - [in] Register number to identify buffer length for register address.
UINT16 AddrData[ ] – [in] Array of address and data pair, caller is responsible for allocating buffer that is big enough.
# Returns:
int – status of if write register successfully.
0 – write data to cbus register successfully
1 – write data operation time out
100 – write data interrupt error
# Notes:
Address and data are all in 16 bits.
# ReadCBus
# Synopsis:
SINT32 ReadCBus (UINT16 addr, UINT16\* data)
# Description:
This function reads a register on the C-bus.
# Arguments:
UINT16 addr – [in] register address of read from
UINT16 \*data – [out] data read from register
# Returns:
SINT32 – status of if read register successfully.
0 - success
1 – download buffer error
2 - check interrupt pipe error
# WriteCBus
# Synopsis:
SINT32 WriteCBus (UINT16 addr, UINT16 data)
# Description:
This function writes data to c-bus.
# Arguments:
UINT16 addr – [in] register address to write to
UINT16 data – [in] data to write to a register
# Returns:
SINT32 – status of if write to C-bus register
0 – write data to cbus successfully
1 – write data operation time out
100 – write data interrupt error
# I2C\_WriteRegister
# Synopsis:
int I2C\_WriteRegister (UINT16 Addr, UINT8 Data)
# Description:
This function writes I2C registers for programming/debugging purpose.
# Arguments:
UINT16 Addr – [in] I2c register address
UINT8 Data – [in] data to write to I2C register
# Returns:
int – status of I2C write register operation.
0 – write I2C register successfully
1 – write I2C register interrupt time out or read CBus error
2 – write I2C control register error
3 – write I2C loaddr register error
4 – write I2C data register error
5 – write i2c\_devaddr\_upaddr\_reg register error
100 – write I2C register interrupt error
# GPIO\_Read
# Synopsis:
int GPIO\_Read(SINT32 Index, SINT32 \*pValue)
# Description:
This function read a signal on a GPIO pins.
# Arguments:
SINT32 Index – [in] Index of GPIO pins, should be between 0 and 4. Pin0 and Pin1 are used for channel ID; Pin2, Pin3, and Pin4 are used for Card ID.
SINT32 \*pValue – [out] The signal of GPIO pin.
# Returns:
int – status of GPIO read operation.
0 – read GPIO successfully
ERR\_DEVICE (0x0001) – device operation failed.
ERR\_PARAMETER(0x0007) – bad parameter of Index.
# 5.4 WIS-LIVE Interface
WIS-LIVE is an interface to convert the encoded A/V stream to the LIVE streaming libraries which is an OpenSource library.
WIS-LIVE provides the following two libraries:
Wis-live is a library containint the APIs for go-server application.
Wis-live\_stand is a library containing the APIs for live-server application.
# WIS-LIVE APIs
# PlayMPEG4AudioVideoStream
# Synopsis:
```txt
void PlayMPEG4AudioVideoStream(StreamBufQueue_t * pABuf,
StreamBufQueue_t* pVBuf,
char *pIpAddr,
int Aport,
int Vport,
int RTSPport,
int audioIsPCM)
```
# Description:
This function can be used to play MPEG4 video and mp2 audio with Live.com library.
# Arguments:
StreamBufQueue\_t \*pABuf – [in] Pointer to audio buffer queue
StreamBufQueue\_t \*pVBuf – [in] Pointer to video buffer queue
char \*plpAddr – [in] destination ip address, NULL means use Unicast
int Aport – [in] audio destination port
int Vport – [in] video destination port
int RTSPport – [in] rtsp listen port
int audiolsPCM – [in] whether the input audio stream is raw PCM rather than MPEG audio
# Returns:
None;
# PlayMPEG1or2AudioVideoStream
# Synopsis:
```txt
void
PlayMPEG1or2AudioVideoStream(StreamBufQueue_t * pABuf,
StreamBufQueue_t * pVBuf,
char *pIpAddr,
int Aport,
int Vport,
int RTSPport,
int audioIsPCM)
```
# Description:
This function is used to play MPEG1 and MPEG2 AV with Live.com library.
# Arguments:
StreamBufQueue\_t \*pABuf – [in] Pointer to audio buffer queue StreamBufQueue\_t \*pVBuf – [in] Pointer to video buffer queue char \*plpAddr – [in] destination ip address, NULL means use Unicast
int Aport – [in] audio destination port
int Vport – [in] video destination port
int RTSPport – [in] rtsp listen port
int audiolsPCM – [in] whether the input audio stream is raw PCM rather than MPEG audio
# Returns:
None;
# WIS-LIVE-STAND APIs
# PlayAudioVideoStream
# Synopsis:
```txt
void PlayAudioVideoStream( FrameReadFunc* aRead, FrameReadFunc* vRead,
char *pIpAddr,
int Aport,
int Vport,
int RTSPport,
char* RTSPaddr,
int audioNumChannels,
int audioSamplingRate,
int audioOutputMode,
int videoOutputMode,
char const* allowedUsername,
char const* allowedPassword)
```
# Description:
This function is used to play MPEG4 video and mp2 audio with Live.com library.
# Arguments:
ReadFrameFunc \*aRead – [in] functions that read audio/video frames
ReadFrameFunc \*vRead – [in] functions that read audio/video frames
char \*plpAddr - [in] destination ip address, NULL means use Unicast
int Aport – [in] audio destination port
int Vport – [in] video destination port
int RTSPport – [in] rtsp listen port
char\* RTSPaddr - [in] IP address to use for RTSP server (NULL for default)
int audioNumChannels – [in] number of channels of PCM audio
int audioSamplingRate – [in] sampling frequency of audio (if PCM only)
int audioOutputMode – [in] the mode of audio output.
0: => 16-bit PCM;
1: => 8-bit u-law;
any other value (x) => x kbps MPEG-1 audio
int videoOutputMode – [in] the mode of video output
0: => MPEG-4;
1: => H.263
char const\* allowedUsername – [in] user name to authorize access to the server;
NULL to allow anyone access
char const\* allowedPassword - [in] password to authorize access to the server;
NULL to allow anyone access
# Returns:
None;
# WIS-LIVE Structure
StreamBufQueue\_t
```txt
typedef struct StreamBufQueue_s
{
struct stream_buf_s stream_buf[MAX_NUM_BUFFER];/
/stream buffer queue
int head; // queue header, value is between 0 - MAX_NUM_BUFFER
int tail; // queue tail, value is between 0 - MAX_NUM_BUFFER
int type; // 1: audio stream buffer queue, 2: video stream buffer queue
pthread_mutex_t mutex; //pthread mutex
} StreamBufQueue_t ;
```
Stream\_buf\_s
```c
struct stream_buf_s
{
char *p; // buffer pointer
char *cur; // Current position
int len; // the current string length
struct timeval creationTime; // when the data was created
};
#define MAX_NUM_BUFFER 128
```
# 5.5 OSD APIs
# Purpose
This section describes how to use OSD APIs.
# API Description
# init\_osd
# Synopsis:
osd\_error\_t init\_osd (void \*pdxc, long video\_frame\_width, long video\_frame\_height)
# Description:
This function initializes the encoder chip to handle OSD command.
# Arguments:
void \*pdxc - [in] pointer to DEVICE\_EXTENSION\_COMMON struct. User is responsible for its allocation and initialization.
long video\_frame\_widht – [in] width of input video frame. Unit is number of pixels.
long video\_rame\_height - [in] height of input video frame. Unit is number of pixels.
# Returns:
osd\_error\_t: return the status of OSD initialization. osd\_error\_t is a enumeration type defined in src/drv/osd.h
OSD\_ERROR\_OUTOFMEMORY - system has not enough memory for osd.
OSD\_ERROR\_OK – initialization succeed.
# Notes:
This function is called when initializing device.
# get\_osd\_frame
# Synopsis:
osd\_error\_t get\_osd\_frame (unsigned char num, void \*string\_ptr)
# Description:
This function actually transfers to be displayed string from user program to the OSD internal buffer.
# Arguments:
unsigned char num – [in] number of osd string. User shall specify a set of X, Y coordinates and data strings in the following structure passed by \*string\_ptr. This is number specifies number of valid strings in the structure.
void \*string\_ptr - [in] in order to show osd correctly, user should pass a pointer to osd\_string\_t struct defined in Include/osd.h:
The struct of osd\_string\_t contains the following:
unsigned char x: the x coordinate of the location to show osd; unit is number of macro blocks (a macro block is 16\*16 pixels)
unsigned char y: the y coordinate of the location to show osd; unit is number of macro blocks (a macro block is 16\*16 pixels).
Example: Preview window is 720\*480, max value of x is 720/16-1=44, max value of y is 480/16-1 = 29.
char osd\_string[]: the content of string text. The max lenght is OSD\_STRING\_LEN\_MAX -3
# Returns:
osd\_error\_t - return OSD\_ERROR\_OK, get OSD frame successfully.
# Notes:
The function name should be named as send\_osd\_data(void \*string\_ptr).
# show\_osd\_frame
# Synopsis:
osd\_error\_t show\_osd\_frame (osd\_display\_mode\_t mode)
# Description:
This function writes the prepared OSD data to OSD font index buffer for chip to display.
# Arguments:
osd\_display\_mode\_t mode - [in] the mode to update current buffer of write to a new buffer.
OSD\_NORMAL: 0
OSD\_REFRESH: 1
# Returns:
osd\_error\_t – return the status of OSD show.
OSD\_ERROR\_BUS\_WRITE\_FAIL – write CBus failed.
OSD\_ERROR\_OK - succeed.
# Notes:
# clean\_osd
# Synopsis:
osd\_error\_t clean\_osd ()
# Description:
When user want to clear the strings displayed by osd, just call this function.
# Arguments:
None
# Returns:
osd\_error\_t - return the status of OSD clean.
OSD\_ERROR\_OK – clean OSD successfully.
# Notes:
# Example:
Here is an example to show how to use OSD APIs.
# 1. initialize OSD
```c
In the function initializeDevice(PDEVICE_EXTENSION_COMMON context), call function init_osd() to initialize OSD.init_osd(context, video_config->rescfg.width, video_config->rescfg.height);
```
# 2. send string to OSD module
```c
sd_string_t osd_str[2] = {
{1, 6, "How are you today?"}, {4, 9, "Wish you a good day"}
};
get_osd_frame(2, &osd_str[0]);
```
# 3. show OSD
```javascript
show_osd_frame(0);
```
It will show the string “How are you today?” at $(1,6)$ macro block.
"Wish you a good day" at (4,9) macro block.
# 4. clear OSD
```txt
clean_osd();
```
# 5.6 FFMPEG APIs
FFMPEG is a very fast video and audio converter. It can also grab from a live audio/video source. The command line interface is designed to be intuitive, in the sense that FFMPEG tries to figure out all the parameters, when possible. You have usually to give only the target bit rate you want.
FFMPEG can also convert from any sample rate to any other, and resize video on the fly with a high quality poly-phase filter.
FFMPEG provides the following two libraries:
Libavcodec is the library containing the codecs (both encoding and decoding). See \`libavcodec/apiexample.c' to see how to use it.
Libavformat is the library containing the file formats handling (mux and demux code for several formats). See \`ffplay.c' to use it in a player. See \`output\_example.c' to use it to generate audio or video streams.
You can integrate all the source code of the libraries to link them statically to avoid any version problem. All you need is to provide a 'config.mak' and a 'config.h' in the parent directory. See the defines generated by ./configure to understand what is needed.
Some of FFMPEG APIs are called by methods of CServer. Main FFMPEG APIs will be described in this section. User can customize its own CServer for its own functionality using FFMPEG APIs.
# AV CODEC APIs
# register\_avcodec
# Synopsis:
void register\_avcodec(AVCodec \*format)
# Description:
This function is used for registering CODEC; the specified CODEC will be linked to the CODEC list first\_avcodec;
# Arguments:
AVCodec \*format – [in] Points to the specified CODEC to be registered;
# Returns:
None;
# avcodec\_find\_encoder
# Synopsis:
AVCodec \*avcodec\_find\_encoder(enum CodecID id)
# Description:
This function is used for finding the specified encoder in the CODEC list first\_avcodec of FFMPEG.
# Arguments:
enum CodecID id – [in] The CODEC id of the encoder to be found;
# Returns:
AVCodec \* - null, not found; Or the pointer to the struct AVCode for the encoder found.
# avcodec\_find\_decoder
# Synopsis:
AVCodec \*avcodec\_find\_decoder(enum CodecID id)
# Description:
This function is used for finding the decoder according to the specified CODEC id in the CODEC list first\_avcodec of FFMPEG.
# Arguments:
enum CodecID – The CODEC id of the decoder to be found;
# Returns:
AVCodec \* - null, not found; Otherwise, the pointer to AVCodec of the CODEC found;
# avcodec\_open
# Synopsis:
int avcodec\_open(AVCodecContext \*avctx, AVCodec \*codec)
# Description:
This function opens the specified CODEC in order to code or encode.
# Arguments:
AVCodecContext \*avctx – Points to the context of the CODEC.
AVCodec \*codec – Points to the CODEC used for coding or encoding.
# Returns:
int – status of open:
-1 – the codec has been open
0 – open successfully
12 – not big enough memory to allocate
<0 – the codec initialized failed
# avcodec\_close
# Synopsis:
int avcodec\_close(AVCodecContext \*avctx)
# Description:
This function is used for closing the specified CODEC not to be used for coding or encoding any more;
# Arguments:
AVCodecContext \*avctx – Points to the context of the CODEC;
# Returns:
int - 0;
# avcodec\_encode\_audio
# Synopsis:
int avcodec\_encode\_audio(AVCodecContext \*avctx,
uint8\_t \*buf,
int buf\_size,
const short \*samples)
# Description:
This function is used for encoding an audio stream.
# Arguments:
AVCodecContext \*avctx - [in] Points to the CODEC context used for encoding audio stream.
uint8\_t \*buf - [out] Points to the buffer for storing the returned encoded audio stream.
int buf\_size - [in] The buffer size of the buffer pointed to by buf.
const short \*samples – [in] Points to the buffer storing the audio stream.
# Returns:
int – status of audio encoding:
-1, error;
Others, the number of bytes of returned encoded audio stream;
# avcodec\_decode\_audio
# Synopsis:
int avcodec\_decode\_audio(AVCodecContext \*avctx,
int16\_t \*samples,
int \*frame\_size\_ptr,
uint8\_t \*buf,
int buf\_size)
# Description:
This function is used for decoding an audio frame.
# Arguments:
AVCodecContext \*avctx - [in] Points to the context of the CODEC used for decoding audio stream;
int16\_t \* samples – [out] Points to the buffer for storing the decompressed audio stream;
int \*frame\_size\_ptr -- [out] Points to the variable used for storing the decompressed size in BYTES.
uint8\_t \*buf - [in] Points to the buffer storing the audio stream to be decompressed;
int buf\_size -- [in] The size of the audio stream to be decompressed;
# Returns:
int - 1, error; Others, the number of bytes have been used by decompressing
# avcodec\_encode\_video
# Synopsis:
int avcodec\_encode\_video(AVCodecContext \*avctx,
uint8\_t \*buf,
int buf\_size,
const AVFrame \*pict)
# Description:
This function is used for encoding video stream.
# Arguments:
AVCodecContext \*avctx -[in] Points to the CODEC context used for encoding video stream;
uint8\_t \*buf - [out] Points to the buffer for storing the returned encoded video stream;
int buf\_size - [in] The buffer size of the buffer pointed to by buf;
const AVFrame \*pict – [in] Points to the buffer storing the video stream to be encoded.
# Returns:
int – The size of the encoded output stream in bytes;
# avcodec\_decode\_video
# Synopsis:
int avcodec\_decode\_video(AVCodecContext \*avctx,
AVFrame \*picture,
int \*got\_picture\_ptr,
uint8\_t \*buf,
int buf\_size)
Description:
This function is used for decoding a frame;
# Arguments:
AVCodecContext \*avctx - [in] Points to the context of the CODEC used for decoding the video;
AVFrame \*picture – [out] Points to an AVFrame
int \*got\_picture\_ptr - [out] 0, No frame could be decompressed; otherwise, it is nonzero;
uint8\_t \*buf - [in] Points to the begin of bit stream buffer, must be FF\_INPUT\_BUFFER\_PADDING\_SIZE larger then the actual read bytes because some optimized bit stream readers read 32 or 64 bit at once and could read over the end;
int buf\_size - [in] The size in bytes of the buffer pointed by buf;
# Returns:
int -1, error; Others, the number of bytes have been used for decompressing;
# avpicture\_get\_size
# Synopsis:
int avpicture\_get\_size(int pix\_fmt, int width, int height)
# Description:
This function used for getting the necessary buffer size for the raw picture to be encoded;
# Arguments:
int pix\_fmt – Pixel format of the raw picture to be encoded;
int width – Width in pixel for the raw picture to be encoded;
int height – Height in pixel for the raw picture to be encoded;
# Returns:
int – the size in bytes for the raw picture to be encoded;
# avpicture\_fill
# Synopsis:
int avpicture\_fill(AVPicture \*picture, uint8\_t \*ptr, int pix\_fmt, int width, int height)
# Description:
This function is used for setting the data[i] and linesize[i] (the range of i is from 0 to 2) fields through computation.
# Arguments:
AVPicture \*picture – [in] Points to the AVPicture whose data and linesize field is to be filled;
uint8\_t \*ptr - [in] data[0] field is filled with ptr;
data[1] is the start address for Y data; data[1] is the start address for U data;
data[2] is the start address for V data;
int pix\_fmt - [in] Pixel format of the raw picture;
int width – [in] Width in pixel of the raw picture;
int height – [in] Height in pixel of the raw picture;
# Returns:
int - 1, the input pixel format cannot be recognized; Others, the size in bytes for the raw picture to be encoded
# av\_mallocz
# Synopsis:
void \*av\_mallocz(unsigned int size)
# Description:
This function is used for allocating memory for libavcodec; the allocated memory is aligned at 16-byte boundary.
# Arguments:
unsigned int size – The specified size of memory to be allocated;
# Returns:
void \* - null, no memory can be allocated; Others, points to the allocated memory;
# avcodec\_alloc\_context
# Synopsis:
AVCodecContext \*avcodec\_alloc\_context(void)
# Description:
Allocates an AVCodecContext and set it to defaults.
# Arguments:
None
# Returns:
AVCodecContext \* - null, no memory can be allocated;
The pointers to the allocated AVCodecContext;
# Notes:
This can be deallocated by simply calling free();
# avcodec\_alloc\_frame
# Synopsis:
AVFrame \*avcodec\_alloc\_frame(void)
# Description:
This function is used for allocating an AVFrame and set it to defaults.
# Arguments:
None;
# Returns:
AVFrame \* - null, no AVFrame is allocated;
Others, the pointer to the allocated AVFrame;
# Notes:
This can be deallocated by simply calling free().
This function uses av\_mallocz to allocate memory; so the allocated memory is 16-byte alignment
# avcodec\_get\_context\_defaults
# Synopsis:
void avcodec\_get\_context\_defaults(AVCodecContext \*s)
# Description:
This function is used for setting CODEC context with default values;
# Arguments:
AVCodecContext \*s - [in] Pointer to the CODEC context to be set with default values;
# Returns:
None.
# AV Format APIs
# register\_protocol
# Synopsis:
int register\_protocol(URLProtocol \*protocol)
# Description:
This function is used for registering file I/O operations.
# Arguments:
URLProtocol \*protocol – Points to the URLProtocol to be registered;
# Returns:
int - 0;
# mpegps\_init
# Synopsis:
int mpegps\_init(void)
# Description:
This function is used for registering the MPEGI and MPEG II formats;
# Arguments:
None;
# Returns:
int 0;
raw\_init
# Synopsis:
int raw\_init(void)
# Description:
This function is used for registering with the following raw formats:
Input format: ac3; h263; MPEG4; H264; MPEG video; MJPEG video; raw video;
For output format, null raw video is added besides the above formats;
# Arguments:
None;
# Returns:
int - 0;
# mp3\_init
# Synopsis:
int mp3\_init(void)
# Description:
This function is used for registering with the following formats,
Input: mp3;
Output: mp2, mp3;
# Arguments:
None;
# Returns:
int - 0;
# wav\_init
# Synopsis:
int wav\_init(void)
# Description:
This function register wave format;
# Arguments:
None;
# Returns:
int - 0;
# guess\_format
# Synopsis:
AVOutputFormat \*guess\_format(const char \*short\_name,
const char \*filename,
const char \*mime\_type)
# Description:
This function is used for finding the matched output file format. It will match according the following parameters: short\_name, mime\_type, filename;
# Arguments:
const char \*short\_name - [in] File name;
const char \*filename –[in] File extension;
const char \*mime\_type –[in] Mime type;
# Returns:
AVOutputFormat \* - Null, no matching file format exist; Others, the pointer to the matched file format;
# url\_fopen
# Synopsis:
int url\_fopen(ByteIOContext \*s, const char \*filename, int flags)
# Description:
This function opens a file with a registered URLProtocol.
# Arguments:
ByteIOContext \*s – [out] A pointer to ByteIOContext, its fields will be set according to the specified filename and flags;
const char \*filename - [in] The filename of the file to be opened;
int flags -- #define URL\_RDONLY 0
#define URL\_WRONLY 1
#define URL\_RDWR 2
# Returns:
int – status of file open:
0, ok;
-ENOMEM, no memory;
-EIO, IO error;
# Notes:
When opened as read/write, the buffers are only used for reading.
# url\_fclose
# Synopsis:
int url fclose(ByteIOContext \*s)
# Description:
This function is used for freeing the buffer allocated to the specified byte IO context;
# Arguments:
ByteIOContext \*s – [in] Pointer to the ByteIOContext, the buffer of which will be freed.
# Returns:
0, ok;
Others, IO error;
Decided by the registered URLProtocol;
# av\_write\_frame
# Synopsis:
int av\_write\_frame(AVFormatContext \*s,
int stream\_index,
const uint8\_t \*buf,
int size)
# Description:
Write a packet to an output media file. The packet shall contain one audio or video frame.
# Arguments:
AVFormatContext \*s – [in] Media file handle;
int stream\_index – [in] Stream index;
const uint8\_t \*buf - [in] Points to buffer containing the frame data;
int size – [in] Size of buffer in bytes;
# Returns:
int – status of frame write
< 0, error,
= 0, ok,
=1, end of stream wanted.
# av\_set\_parameters
# Synopsis:
int av\_set\_parameters(AVFormatContext \*s, AVFormatParameters \*ap)
# Description:
This function currently is only used for setting pixel format if not YUV420P
# Arguments:
AVFormatContext \*s – [in] Media file handle;
AVFormatParameters \*ap - [in] Pointer to the audio/video parameters structure
# Returns:
int – status of parameters setting
0, OK;
<0, Error;
Others, no use;
# av\_write\_header
# Synopsis:
int av\_write\_header(AVFormatContext \*s)
# Description:
Allocate the stream private data and write the stream header to an output media file
# Arguments:
AVFormatContext \*s - media file handle
# Returns:
int - 0, ok; AVERROR\_xxx, error.
# av\_probe\_input\_format
# Synopsis:
AVInputFormat \*av\_probe\_input\_format(AVProbeData \*pd, int is\_opened)
# Description:
This function is used for detecting file or stream format.
# Arguments:
AVProbeData \*pd – The pointer to the AVProbeData containing the data to be checked. The following fields of filename: buf, buf\_size of this should be set;
int is\_opened - 1, file is opened;
0, file is not opened;
# Returns:
AVInputFormat \* - null, not found;
Others, points to the AVInputFormat matching the specified stream of file;
# av\_write\_trailer
# Synopsis:
int av\_write\_trailer(AVFormatContext \*s)
# Description:
This function is used for writing the stream trailer to an output media file and free the file private data.
# Arguments:
AVFormatContext \*s – [in] media file handle
# Returns:
int - 0, OK; AVERROR\_xxx, error.
# av\_gettime
# Synopsis:
int64\_t av\_gettime(void)
# Description:
This function is used for getting system time in microseconds;
# Arguments:
None
# Returns:
int64\_t - System time in microseconds;
# av\_new\_stream
# Synopsis:
AVStream \*av\_new\_stream(AVFormatContext \*s, int id)
# Description:
This function is used for adding a new stream to a media file.
# Arguments:
AVFormatContext \*s - Media file handle;
int id - File format dependent stream id;
# Returns:
AVStream \* - Null, no stream can be allocated; Others, the pointer to the allocated AVStream;
# Notes:
It can only be called in the read\_header function.
If the flag AVFMTCTX\_NOHEADER is in the format context, then new streams can be added in read\_packet too.
# dump\_format
# Synopsis:
void dump\_format(AVFormatContext \*ic,
int index,
const char \*url,
int is\_output)
# Description:
This function dumps the audio / video format to standard output.
# Arguments:
AVFormatContext \* - [in] Points to the AVFormatContext to be dumped;
int index – not used;
const char \*url – [in] Pointer to the sting for URL;
int is\_output - [in] 1 on output; 0 on input;
# Returns:
None;
# av\_write\_header
# Synopsis:
int av\_write\_header(AVFormatContext \*s)
# Description:
Allocate the stream private data and write the stream header to an output media file
# Arguments:
AVFormatContext \*s –[in] Media file handle;
# Returns:
int - 0, OK; AVERROR\_xxx, error;
# Structures and Constants
Pease refer to libavcodec\avcodec.h for the following structures and constants:
```csv
AVCodec
AVCodecContext
AVFrame
AVPicture
enum CodecID
```
Please refer to libavformat\Avformat.h for the following structures and constants:
```txt
AVFormatContext
AVProbeData
AVStream
AVFormatParameters
```
Please refer to libavformat\avio.h for the following structures and constants:
```txt
ByteIOContext
URLProtocol
```
Please refer to libavcodec\common.h for the following types:
```c
int16_t
uint8_t
int64_t
```
# 5.7 CServer Interface
# Purpose
CServer is an application level class developed based on CVideoCapture. This class includes a series of methods through calling Linux thread APIs to implement its own functions. These methods presenting the go-server features are implemented in this class.
Method Summary
<table>