Sound sync prob. DVB-S -> DVD via Tmpgenc Author

[robmack]

I capture DVB-S MPEG-2 data streams from satellite to disk using a Haupauge Win-TV Nexus card. When I try to convert these streams with Tmpgenc and author a DVD with Tempgenc Author, I always get a sound sync problem -- sound is delayed by about 500mS from the video. All Tmpgenc software is the latest version.

The source stream is:
DVD PAL (Mpeg-2, 720x576, 25fps, CBR 8Mbps, Linear PCM 48K)
The output stream ready for burning to the DVD is:
low resolution (mpeg-2, 352x288, 25fps, CBR, 2Mbps, linear PCM 48K)

I've experimented both with separate M2V/WAV files and combined MPG file. Both exhibit the same sync problem. I am reducing the bit rate to reduce the file size so that I can fit 6 half-hour programs on a DVD. Otherwise the frame and audio rates remain the same.

Where is this sync problem coming from and how do I fix it in Tmpgenc?

[yuffy]

I not an expert but why 352x288, I thought that was a VCD setting. For DVD pal it should be 720x576.
Try to increase your bitrate to 8000 CBR as per your source.
Three hours for a DVD?
I'm cautious, so I record 1 hour with a backing track & motion menu.
But I know that for DVDworkshop the max for 90 mins is 2 pass vbr.
So answer is change your bit rate, change your size & def change the length of your time for DVD.

[robmack]

Hmm, well I made a slight error on the source datastream specs (which are 16:9 PAL BTW) so I'll correct myself:

Mpeg-2, resolution 544x576, 25 fps, 15Mbps, linear PCM 48k

So, when I authored the datastreams for the DVD, I down-converted the resolution to low-resolution PAL (320x576) instead of up-converting the resolution which would have introduced distortion. As it stands, Tempgenc Author won't accept the source data stream. It would be nice because I would avoid all sorts of coversion problems but such is life.

The source has a file size of about 730MB, the converted stream is half this size. I can try to up the resolution to 704x576 or 720x576 to see what happens but if I maintain the bitrate at 8M, the file size will increase to maybe 800M which means I might only fit 5 half hour programs on a DVD. Ok, it's only one program short but the series is only six programs in total and it was soooo convenient to fit it all onto one DVD.

[bugster]

So, when I authored the datastreams for the DVD, I down-converted the resolution to low-resolution PAL (320x576) instead of up-converting the resolution which would have introduced distortion.

Don't you mean 352*576. Thats a valid DVD res and TmpGenc DVD author will accept that.

As for the audio issue, maybe the audio is offset in the original mpeg source file. If that is the case, use Tmpgenc Source range option where there is an aidio gap correct setting. This should allow you to bring the audio back in to line.

[ronnylov]

I recommend using PVAStrumento to fix your dvb-s recordings.
Normally I capture in PVA format (but it can fix mpg too) and then use pvastrumento to fix video and audio errors to make it DVD compliant. This will probably fix your sync problems. You'll probably also see that it will correct the average bitrate value (I'm pretty sure it's not 15 mbit/s, the dvb streams often reports too high bitrate).

If you want to encode it with tmpgenc then load the video and audio sources that you got from pvastrumento demuxing into tmpgenc. But if you use DVDlab it may work to author a DVD directly with the non-standard resolution. It depends if your DVD-player supports it.

An alternative to use tmpgenc could be author the DVD with DVDlab first and then use DVDShrink to make it fit one disc.

[robmack]

Thanks for the suggestion, ronnylov. It appears that I may be able to avoid using PVAStrumento (which I have but don't use).

I have experimented some more since posting, using some of the suggestions from bugster. What I've done is to change the output format from PAL to 16:9 display, interlace to non-interlace, size to 720x576 and biterate from 2Mb to 4Mb. I also edit the source range in Tempgenc at the conversion stage instead of in Tmpgenc DVD Author during the authoring stage. The filesize ends up being about 820MB which means I can fit about 4 half-hour programs on the DVD meeting the DVD-5 spec. End result is good; the audio delay is 0mS. I'm experimenting with 3Mb bitrates to see if I can fit 5 half-hour programs on a DVD for my next project.

Thanks to all for pointing me in a new direction to solve my problem.