8.4.0.1. Audio/Video Sources
(packages/ffmpeg/avsource.lsh)




8.4.0.1.0. AVSource
(packages/ffmpeg/avsource.lsh)


Class AVSource is a common superclass for the AudioSource and VideoSource classes.



8.4.0.1.0.0. (==> avsource process)
[MSG] (packages/ffmpeg/avsource.lsh)


This internal function is called when new data is available for the source.



8.4.0.1.1. AudioSource
(packages/ffmpeg/avsource.lsh)


See: AvAudioSource
The abstract class AudioSource defines generic methods that enable access to a stream of audio data. The actual work is performed by related subclasses, such as AvAudioSource .

WARNING : Currently, this class is not usable.



8.4.0.1.1.0. (==> audiosource nextframe)
[MSG] (packages/ffmpeg/avsource.lsh)


Method nextframe obtains the next segment of audio data. It returns t if new audio data is available, and returns () when it reaches the end of an audio stream.

After initialization of an audio source, this method must be called once in order to access the first segment of audio data.



8.4.0.1.2. VideoSource
(packages/ffmpeg/avsource.lsh)


See: AvAudioSource
The abstract class VideoSource defines generic methods to enable access to a stream of video data. The actual work is performed by related subclasses, such as AvVideoSource .



8.4.0.1.2.0. (==> videosource nextframe)
[MSG] (packages/ffmpeg/avsource.lsh)


Method nextframe obtains the next video frame. It returns t if a new frame can be accessed using the frame access methods get-frame-xxx , and returns () when reaching the end of the video stream.

After initialization of a video source, this method must be called once in order to access the first video frame.



8.4.0.1.2.1. (==> videosource get-frame-pts)
[MSG] (packages/ffmpeg/avsource.lsh)


Returns the presentation time stamp of the current frame. The presentation time stamp is a real number expressed in seconds. Calling this function before the first call to nextframe gives the starting time of a movie.



8.4.0.1.2.2. (==> videosource get-frame-gray)
[MSG] (packages/ffmpeg/avsource.lsh)


Returns the gray level image associated with the current frame as a two dimensional matrix of unsigned bytes.



8.4.0.1.2.3. (==> videosource get-frame-rgba)
[MSG] (packages/ffmpeg/avsource.lsh)


Returns the RBGA image associated with the current frame as a three dimensional matrix of unsigned bytes. The last dimentsion contains four elements: three color components (R, G, B) and one alpha channel (A).



8.4.0.1.2.4. (==> videosource get-frame-yuv)
[MSG] (packages/ffmpeg/avsource.lsh)


Returns the YUV image associated with the current frame as a three dimensional matrix of unsigned bytes. The last dimension contains three elements, one per color component (Y, U, V).