Fast DVD not working? Frame data underruns

[bigjuggler]

Hi,

As usual Major, your excellent app keeps getting better.

I have been trying to use the fast DVD preset to encode a couple of XVID movies to DVD widescreen.

I have done two of them and both encodings failed with this error:

**ERROR: [mplex] MUX STATUS: Frame data under-runs detected!

It still produced an .mpv and .ac3 file as well as a muxed .mpg. The files play fine in VLC and Quicktime (without AC3 of course). FfmpegX will not author a DVD (I am using 0.9f), but Sizzle did. The resulting DVD plays fine in Apple's DVD player, but is jerky with some audio stutters on both of my set players.

I suspect this is because of these "under-runs".

I have to say that I am very, very impressed with the quality of the encode (despite the jerkiness). I have not done carefull looking yet, but my initial impression is that it is better than I get from Apple's encoder on one-pass.

I don't know if this is related but both movies ended up being about 2.3 and 2.7 Gigs as final mpegs (they are 96 and 108 minutes respectively). Does this mean it could be encoded at a higher bit rate for even better quality?

[major]

Could you please email me your process output to major4@mac.com

[Dave Null]

Hi,

I have done two of them and both encodings failed with this error:

**ERROR: [mplex] MUX STATUS: Frame data under-runs detected!

It still produced an .mpv and .ac3 file as well as a muxed .mpg.

(...)
I suspect this is because of these "under-runs".

I've exactly the same pb, with the same message. Have you find a solution ?

[bigjuggler]

I did email Major directly and he kindly offered a couple os suggestions:

(i) Try deactivating decode with Quicktime
(ii) Try increasing Qmax to 30

Unfortunately I have been very busy with work lately and haven't had a chance to test thing thoroughly.

I repaired the index on both divx files and am now trying the encode again. It still looks like the resulting .mpv will be relatively small (about 2 gigs for a 111 min film). I did set the bitrate at about 4500. The encoding quality looks very good again, even at the small filesize. I have encoded this film with Apple's Quicktime MPEG2 as well for comparison.

The FFMPEG encode should be done by morning. I'll let you know what happens.

[bigjuggler]

So here's an update:

Using Mencoder instead of Quicktime to decode does some weird things. It does not generate a separate .m1v and .ac3 file, but instead, seems to build an muxed mpeg as it goes. It doe go on to author to DVD from the resulting mpeg, but the VIDEO_TS file cannot be opened in Apple's DVD player ("could not detect valid media file). If burned to a disk, my desktop players will not play it either.

I am able to play the encoded mpeg in QT fine. Also, if I burn this mpeg to disk, I can play it unauthored in my DVD player (it will play any mpeg unauthored). The video quality is very good. Definitely less blockiness and pixelation that what Apples QT mpeg2 encoder produces.

I ran the same file with Fast DVD but using Quicktime to decode and this time it muxed it fine (reporting no data underruns....maybe the repair on the .avi idex helped). SADLY, the resulting mpeg still plays very poorly on my desktop players. It hesitates or freezes just a bit every 3 or 4 seconds. Otherwise it looks very good. My mac plays it fine. When I tried to demux the mpg, ffmpegx gave me hundred of tiny pieces of files. I am wondering it the packet size if off or something (HINT: I am guessing, i don't really know what I am talking about, just speculating). This mpeg file does not play well as a raw mpeg in my player either....the audio drops out every 3 or 4 seconds and then comes back...no freezing of video thought. Strange no?

One other thing I have noticed. When I get info on this mpeg file (QT decoded and fast DVD encoded) it reports the audio as mpeg 1 instead of AC3. I am not sure if this is important.

So, I must continue to experiment to solve this, since I REALLY like the video that Fast DVD produces. My next step is to encode the audio to mp2 and mux it with the .m1v file and see if my player likes that.

I'll let you know.