same quality lossless in mpeg 2 can be achieved by COPYING original file - what are You doing now i mpeg-2 transcoding and seems that ffmpeg lost information about interlace however it can be case where this is progressive file marked as interlace (pull down?) and ffmpeg transcode source ignoring pull down signalization - thus lower bitrate and progressive structure...
to losslessly resyncing You can try some TS muxer which allow to define offset for audio (delay/advance) is introduced by changing PTS.
http://alien.slackbook.org/blog/fixing-audio-sync-with-ffmpeg/
http://forums.gbpvr.com/showthread.php?49257-audio-out-of-sync-fix-with-ffmpeg!
Only COPY provide lossless operation on lossy compressed formats.
Last edited by pandy; 26th November 2012 at 12:22.
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