Function ffmpeg_sys_next::avcodec_decode_audio4

pub unsafe extern "C" fn avcodec_decode_audio4(
    avctx: *mut AVCodecContext, 
    frame: *mut AVFrame, 
    got_frame_ptr: *mut c_int, 
    avpkt: *const AVPacket
) -> c_int

Decode the audio frame of size avpkt->size from avpkt->data into frame.

Some decoders may support multiple frames in a single AVPacket. Such decoders would then just decode the first frame and the return value would be less than the packet size. In this case, avcodec_decode_audio4 has to be called again with an AVPacket containing the remaining data in order to decode the second frame, etc... Even if no frames are returned, the packet needs to be fed to the decoder with remaining data until it is completely consumed or an error occurs.

Some decoders (those marked with AV_CODEC_CAP_DELAY) have a delay between input and output. This means that for some packets they will not immediately produce decoded output and need to be flushed at the end of decoding to get all the decoded data. Flushing is done by calling this function with packets with avpkt->data set to NULL and avpkt->size set to 0 until it stops returning samples. It is safe to flush even those decoders that are not marked with AV_CODEC_CAP_DELAY, then no samples will be returned.

@warning The input buffer, avpkt->data must be AV_INPUT_BUFFER_PADDING_SIZE larger than the actual read bytes because some optimized bitstream readers read 32 or 64 bits at once and could read over the end.

@note The AVCodecContext MUST have been opened with @ref avcodec_open2() before packets may be fed to the decoder.

@param avctx the codec context @param[out] frame The AVFrame in which to store decoded audio samples. The decoder will allocate a buffer for the decoded frame by calling the AVCodecContext.get_buffer2() callback. When AVCodecContext.refcounted_frames is set to 1, the frame is reference counted and the returned reference belongs to the caller. The caller must release the frame using av_frame_unref() when the frame is no longer needed. The caller may safely write to the frame if av_frame_is_writable() returns 1. When AVCodecContext.refcounted_frames is set to 0, the returned reference belongs to the decoder and is valid only until the next call to this function or until closing or flushing the decoder. The caller may not write to it. @param[out] got_frame_ptr Zero if no frame could be decoded, otherwise it is non-zero. Note that this field being set to zero does not mean that an error has occurred. For decoders with AV_CODEC_CAP_DELAY set, no given decode call is guaranteed to produce a frame. @param[in] avpkt The input AVPacket containing the input buffer. At least avpkt->data and avpkt->size should be set. Some decoders might also require additional fields to be set. @return A negative error code is returned if an error occurred during decoding, otherwise the number of bytes consumed from the input AVPacket is returned.

@deprecated Use avcodec_send_packet() and avcodec_receive_frame().