FAAC Mpeg Version 2 vs 4

[blazerqb11]

I've been using faac for the audio of some videos I've been encoding and have encountered something I don't really understand. I'm using 1.26 and just passing one option: -q 100. The .aac file I out to shows up as "(Version 2)" in media info, but after I've muxed the audio together with the video with mkvmerge It reads as "(Version 4)". I assume the that the Version 2 is correct because that is how it reads while faac is encoding also.

The sound quality is virtually indistinguishable from the source which is a decent quality AC-3 audio from a DVR TV recording. What I want to know is should I be worried about which version it is coming out as, and how can I force it to use the one I want if that is necessary? I tried -mpeg-vers 4 but it gives me a repeating line over and over at the command line.

[menno]

For compatibility reasons it is probably better to flag the file as MPEG-4. It is possible that some tools refuse to handle the file if it's flagged as MPEG-2, even though the bitstream should be identical. It's best to have FAAC output MP4 files by using the -w option on the command line.

[blazerqb11]

For compatibility reasons it is probably better to flag the file as MPEG-4. It is possible that some tools refuse to handle the file if it's flagged as MPEG-2, even though the bitstream should be identical. It's best to have FAAC output MP4 files by using the -w option on the command line.

Thanks for the clarification. So I should just insert -w into my options?

[menno]

Thanks for the clarification. So I should just insert -w into my options?

Yeah, and make sure you use MP4 or M4A as extension for the output files (if you are giving FAAC specific output filenames).