Some MythTV recording transcodes do not keep audio sync

[Ghengis]

I have been transcoding MythTV recordings (from MPEG2 to h264) with the following command line:

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c:\vlc\vlc -vvv --sout-transcode-deinterlace --sout-x264-level=41 %1 :sout=#transcode{vcodec=h264,vb=%2,scale=1,acodec=mp4a,ab=128,channels=2}:duplicate{dst=std{access=file,mux=mp4,dst="d:\mythtemp\temp.mp4"}} vlc:quit

Now, that might be a mess (I'm not exactly an expert), but it gets the job done, most of the time. The result plays back on a PS3 and an Xbox 360, which I'm happy with. What I'm not happy with is that sometimes the result has an audio offset that's consistent throughout the recording. If I look at the original (MPEG2) with Media Info, it shows a "Video0 delay" in milliseconds, but if I look at the VLC output, there's nothing. I think I found an option in the help to do an offset (--audio-desync), but I can't really do batch scripting if I have to manually look up each and every audio offset myself.

This only seems to happen on certain recordings. Here's an example of before and after for a recording that *didn't* break:

Before:

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General #0 Complete name : \\192.168.42.102\myth\pretty\Mister Rogers' Neighborhood - 2008-02-27, 11-30 AM.mpg Format : MPEG-2 Program Format/Family : MPEG-2 File size : 1012 MiB PlayTime : 28mn 31s Bit rate : 4958 Kbps Video #0 PlayTime : 28mn 31s Bit rate : 4230 Kbps Audio #0 Codec : MPEG-1 Audio layer 2 PlayTime : 28mn 31s Bit rate mode : CBR Bit rate : 384 Kbps Channel(s) : 2 channels Sampling rate : 48 KHz Resolution : 16 bits Video0 delay : 23ms Writing library : Xing (new)

After:

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General #0 Complete name : D:\Archives\TV\Mister Rogers' Neighborhood - 2008-02-27, 11-30 AM.mp4 Format : MPEG-4 Format/Info : ISO 14496-1 Base Media Format/Family : MPEG-4 File size : 232 MiB PlayTime : 28mn 31s Bit rate : 1137 Kbps StreamSize : 1.72 MiB Encoded date : UTC 2008-04-09 10:15:38 Tagged date : UTC 2008-04-09 10:15:38 SpecialPlaybackRequirements : QuickTime 6.0 or greater ©enc : vlc 0.8.6c stream output Video #0 Codec : AVC Codec/Family : AVC Codec/Info : MPEG-4 AVC Codec profile : Main@L4.1 Codec settings, CABAC : Yes PlayTime : 28mn 31s Bit rate : 1001 Kbps Width : 720 pixels Height : 480 pixels Display Aspect ratio : 4/3 Frame rate : 29.970 fps Minimum frame rate : 29.441 fps Maximum frame rate : 30.333 fps Standard : NTSC Chroma : 4:2:0 Interlacement : Progressive Bits/(Pixel*Frame) : 0.097 StreamSize : 204 MiB Encoded date : UTC 2008-04-09 10:15:40 Tagged date : UTC 2008-04-09 10:15:40 Audio #0 Codec : AAC LC Codec/Family : AAC Codec/Info : AAC Low Complexity PlayTime : 28mn 31s Bit rate mode : VBR Bit rate : 127 Kbps Channel(s) : 2 channels Channel positions : L R Sampling rate : 48 KHz Resolution : 16 bits StreamSize : 26.0 MiB Encoded date : UTC 2008-04-09 10:15:38 Tagged date : UTC 2008-04-09 10:15:38

Can anyone help?