493: Undecipherable

Transcode MKV (h264) with multiple audio streams to MP4 (AAC)

Transcoding MKV containers using avconv to MP4, so that the files can be processed with Adobe Premiere. The following command copies the video stream (should already be in h264) and convert all audio streams to AAC. All audio streams are sampled to 6 channels (even if the source is only stereo).

avconv -i INPUT.mkv -c:v copy -map 0:0 -c:a aac -map 0:1 -map 0:2 -ab 448k -ac 6 OUTPUT.mp4

The example is for 2 audio streams; just add more -map commands as needed.