* fall back on using AVCodecContext.frame_size, which is not as reliable
* for indicating packet duration. */
frame_size = av_get_audio_frame_duration(enc, enc->block_align);
* fall back on using AVCodecContext.frame_size, which is not as reliable
* for indicating packet duration. */
frame_size = av_get_audio_frame_duration(enc, enc->block_align);