Mencoder - telecine and audio sync

[Questor]

Hi all,

I'm looking for any suggestions.

I've been trying various mencoder options with comskip commercial cutting and was recently trying the telecine option (-mpegopts tsaf:telecine ).

The output file is about 17% smaller than with just cutting, and after viewing several spots within the output mpeg file it is acceptable quality (to me) but the audio isn't synced at all. Note by non-synced I mean it progressively gets worse so that by the end of the video it is playing audio from much earlier in the file.

I've even tried a two step process with -mpegopts tsaf in the first commercial-cutting pass and -mpegopts tsaf:telecine in the 2nd copy-only pass (no edl cutting). The audio IS synced after cutting only but is lost after 2nd telecine pass.

1st pass
mencoder original.mpg -edl original.edl -oac copy -ovc copy -of mpeg -mpegopts tsaf -o cut_video.mpg

2nd pass
mencoder cut_video.mpg -oac copy -ovc copy -of mpeg -mpegopts tsaf:telecine -o telecine.mpg


I'm no expert on mpeg 3 audio, but I'm certain the video has time stamps periodically in the GOPs, so if there were any audio timestamps the player could syncronize them.

Here is the original file information (from mencoder):
VIDEO: MPEG2 480x480 (aspect 2) 29.970 fps 3500.0 kbps (437.5 kbyte/s)
[V] filefmt:2 fourcc:0x10000002 size:480x480 fps:29.97 ftime:=0.0334
==========================================================================
Opening audio decoder: [mp3lib] MPEG layer-2, layer-3
AUDIO: 48000 Hz, 2 ch, s16le, 192.0 kbit/12.50% (ratio: 24000->192000)
Selected audio codec: [mp3] afm: mp3lib (mp3lib MPEG layer-2, layer-3)
==========================================================================
PACKET SIZE: 2048 bytes, deltascr: 245760
videocodec: framecopy (480x480 24bpp fourcc=10000002)
audiocodec: framecopy (format=50 chans=2 rate=48000 bits=16 B/s=24000 sample-1)
Limiting audio preload to 0.4s.
Increasing audio density to 4.

[pBS]

ahh, you're cutting and changing framerate without giving it a chance to adjust... [-ovc copy]
assuming incoming framerate is 29.97, and telecining changes it to 24fps, but there's no recompression so mencoder can't adjust the frames to match...
[watch the messages as it encodes, the telecine part at beginning]

doesn't it complain that the framerate hasn't been changed?
[it should]

basically, incoming video is 29.97, telecining makes that into 24fps and adds 'telecine' flag and keeps 'reported' framerate as 29.97 even tho it's now 24fps..
it does this so players know to 'reverse' the process in player, adding frames for the 24fps to play on a 29.97 hardware...[confusing huh? ]
[hardware is 29.97 only, can't play 24fps without fixups]

but i bet if you leave out the telecine, it's in sync...

to use telecine, you have to use filter on input video, and specify input and output fps...[at least output as 24fps] as adding that flag will tell players it's a 24fps film that should be played at 29.97..

the reason it's so much smaller is the change in framerate...29.97->24fps
[1/5th less]