dvd2avi and TMPGEnc to SVCD questions.

[petrmich]

I ripped a DVD with Smartripper, then proceeded to use dvd2avi without forced film. Using TMPGEnc I encoded using NTSC Film SVCD Template. The result was an in Sync but very chopy and lined output. (it seems like this was a result of DVD2AVI)

Tried using Forced Film in VDV2AVI, result was a beautiful video but progressive ouf ot sync audio when using same template to create SVCD in TMPGEnc. Tried running the VCD Template in TMPGEnc with the same DVD2avi source and the result was in Sync.

DVD2AVI info is a progressive film 16:9, >95% film.

My two questions are

1) Why the poor video flow when running DVD2AVI in non forced film.

2) Why when using the same DVD2AVI output with forced film the audio is in sync when TMPGEnc encodes in VCD format but is progressibley out of sync when the SVCD template is used?

[adam]

You first need to understand what forced film is and what it does. Most dvds store the movie in its original framerate of 24fps and use RTF/RFF flags to telecine the video in real time. The way to verify that your dvd is like this is to preview it in dvd2avi and let it get past the credits, if it says %95 or higher film and stays like that then it is stored as 24fps and forced film WILL work. If you use forced film in this case than dvd2avi will ignore the flags and process the video as 24fps, leaving you with a progressive video being frameserved to your encoder. If you uncheck forced film then dvd2avi uses the flags on the dvd to frameserve your video as interlaced at 29.97fps to your encoder.

It is much better to use forced film and maintain the original 24fps. You have %20 less frames to work with which means your bitrate goes that much farther. With such strict bitrate constraints in the svcd and vcd formats this essentially means you increase the resulting quality by %20. Also since you are working with progressive video instead of interlaced video you eliminate many other potential problems such as desync and interlacing (those visible white lines.)

1)"Why the poor video flow when running DVD2AVI in non forced film"

Because you used the ntscfilm template which uses a framerate of 23.976fps. You frameserved at 29.97 and converted to 23.976, not a good idea. If you choose to not use forced film, which you should only do if your dvd is not stored as film, then you must use the ntsc template in TMPGenc, NOT the ntsc film template.

2) "Why when using the same DVD2AVI output with forced film the audio is in sync when TMPGEnc encodes in VCD format but is progressibley out of sync when the SVCD template is used?"

From my experience dvd2avi has bugs when it comes to processing audio. If you use forced film and allow dvd2avi to decode your audio you will often get sync problems, but this usually only happens with mpeg2. Svcds use different methods than vcds do to maintain sync, I don't know why but dvd2avi's sync problem only seems to present itself when encoding to mpeg2. The solution is to set dvd2avi to use forced film but in the audio tab set it to demux instead of decode. This will give you an ac3 file which you can properly encode to mp2 using more stable programs like azid, graphedit + direct show filters, or vob2audio. I recommend getting BeSweet, its a gui that uses arguably the best audio conversion method in an all in one type of package. You can find it and guides on how to use it at www.doom9.net.

[petrmich]

ADAM,

THANKS FOR THE REPLY. SO IF I DEMUX THE AC3 FILE WITH DVD2AVI I CAN THEN USE BESWEET TO ENCODE IT INTO A MPEG2 AFTER WHICH I USE TMPGEnc TO ENCODE THE MEPG2 AND THE *.d2v FILE TO CREATE MY FINAL MPGE2. IS THIS CORRECT?

[adam]

Use TMPGenc to encode the video stream (m2v) alone without any audio source.

Use besweet to encode your audio stream (m2p.)

Finally use bbmpeg to multiplex both streams into an mpg file. If you encode the audio and video together in TMPGenc then it will not add the proper svcd scan offsets and you may have sync problems.