Sync problem from DVB capture in MPEG2

[Lucius Snow]

Hello all,

I downloaded a concert captured from digital TV in MPG (MPEG 2 for video / MPEG 1 Layer 2 for sound). It plays fine on WinDVD and Windows media player 9.

I'd like to make a DVD with it but i get a progressive desynchronisation at the rendering whatever the authoring program i use. By doing some searches on the forum, i found out that PVAStrumento should correct this. So i gave it a try but it didn't solve anything. I used :
- "Make PV" with 2048 for "Packet size"
- "Do short scans"
- "Do long scan over over 200"
- "Do long scan over over 500"

Also, i made directly a demutiplexing. Here are all the possibilities i tried. None of them gave me good results.

Any help appreciated.
Thanks, cheers :)

[Lucius Snow]

By the way, here is the log of a scan of my video in PVAStrumento :

*** PVAStrumento 2.0.30
*** running at 11-09-2003 13:38
***
Stream info for
E:\FTPshare\Music\Video\Radiohead\Les eurockéennes 2003\Radiohead - Les
Eurockennes 2003 - MPG2HQ.mpg
VIDEO: Resolution 720 x 576
(full D1)
Aspect ratio is 4:3
Frame rate 25.00 fps
Nominal bitrate 1698400 bps
first PTS: 00:08:00.160
AUDIO: MPEG-1, Layer 2
48.0 kHz, Stereo
Bitrate 256 kbps
Frame Length 24.0 ms (768 bytes)
first PTS: 00:08:00.120
Audio starts 40 ms early
(->video delay on muxing)
==SCANNING==
Syncing: Cutting audio.
No integer frame match for A/V. (around twenty times)
17 audio frame(s) missing at the end.
Done.
Video bitrate: max 5933 , avg 2550 kbps
Video: 136642 pics 01:31:05.680
Audio: 227640 frames 01:31:03.360

[jggimi]

Moved to the HDTV/DVB forum.

[symonjfox]

AFAIK, you should use PVAstrumento @ DEFAULT settings. Else it won't cut properly Audio and Video.

[Lucius Snow]

Okay ... i just made a test with the defaults settings. First, i did a "Demux" so i got both *.mpa & *.mpv files. Then i put them in DVDlab to make the authoring but the rendering was bad. There was a desynchronisation again. Here is the log that PVAstrumento gave me for the "Demux" operation :

VIDEO: Resolution 720 x 576
(full D1)
Aspect ratio is 4:3
Frame rate 25.00 fps
Nominal bitrate 1698400 bps
first PTS: 00:08:00.160

AUDIO: MPEG-1, Layer 2
48.0 kHz, Stereo
Bitrate 256 kbps
Frame Length 24.0 ms (768 bytes)
first PTS: 00:08:00.120

Audio starts 40 ms early
(->video delay on muxing)

==DEMUXING==
Input: E:\FTPshare\Music\Video\Radiohead\Les eurockéennes 2003\Radiohead - Les Eurockennes 2003 - MPG2HQ.mpg
AES: \Radiohead - Les Eurockennes 2003 - MPG2HQ.mpg.mpa
VES: \Radiohead - Les Eurockennes 2003 - MPG2HQ.mpg.mpv
FIXING startup delay.
FIXING stream synch.
ADJUSTING GOP timecodes.

Syncing: Cutting audio.
No integer frame match for A/V. (around x20)
17 audio frame(s) missing at the end.
Done.

Video bitrate: max 5933 , avg 2550 kbps
Setting first sequence header to avg. bitrate

Video: 136642 pics 01:31:05.680
Audio: 227640 frames 01:31:03.360

So i tried "MakePS" operation too which renders a MPG file. At playing in Windows media player, the synchro was good (like for the original file actually). But then again, the video rendering created by the authoring software was desynchronized. Here is the log of "Make PS" operation now :

VIDEO: Resolution 720 x 576
(full D1)
Aspect ratio is 4:3
Frame rate 25.00 fps
Nominal bitrate 1698400 bps
first PTS: 00:08:00.160

AUDIO: MPEG-1, Layer 2
48.0 kHz, Stereo
Bitrate 256 kbps
Frame Length 24.0 ms (768 bytes)
first PTS: 00:08:00.120

Audio starts 40 ms early
(->video delay on muxing)

==MAKING MPEG2 PS==
Input: E:\FTPshare\Music\Video\Radiohead\Les eurockéennes 2003\Radiohead - Les Eurockennes 2003 - MPG2HQ.mpg
MPG: \Radiohead - Les Eurockennes 2003 - MPG2HQ_.mpg
FIXING startup delay.
FIXING stream synch.
ADJUSTING GOP timecodes.

Syncing: Cutting audio.
No integer frame match for A/V(around x20)
17 audio frame(s) missing at the end.
Done.

Video bitrate: max 5933 , avg 2550 kbps
Setting first sequence header to avg. bitrate

Video: 136642 pics 01:31:05.680
Audio: 227640 frames 01:31:03.360

That stuff drives me crazy. :devil:
Any other idea ? Thank you very much.

[bb]

Just two short ideas, because I'm in a hurry:

- Capture in PVA format if you can.
- Try converting your video by ProjectX (Java program), then cut using MPEG2Schnitt.

bb

[Lucius Snow]

I can't capture anything, i don't have a DVB TV card. All i have is this MPG file i must fix to make a DVD.

[ronnylov]

Try the latest beta version of PVAStrumento (I think it is 2.1pre11). It may give better synch.

[Lucius Snow]

I tried with the latest version as well (2.1.0 RC) from November 11th. I'm doing some tests with ProjectX now but they again i get problems :
- if i do "demux", the audio file make around 4 MB instead of 170 MB. I can't get the entire track, i don't know why.
- if i do "to M2P", the audio and video tracks are rebuild completely in a single muxed M2P file but there's always the same desynchro.

For both tests, i let the default settings. If you have any suggestions, let me know. Here is what a scan info in Project X gives me :

=> working with collection 0

-> write output files to :

E:\FTPshare\Music\Video\Radiohead\Les eurockéennes 2003\test\

=> File 0: E:\FTPshare\Music\Video\Radiohead\Les eurockéennes 2003\Radiohead - Les Eurockennes 2003 - MPG2HQ.mpg (2105614776 bytes)

=> File is MPEG-2 PS/SS (Video/Audio PES)

=> demux

-> found PES-ID 0xE0 (MPEG Video)

-> found PES-ID 0xC0 (MPEG Audio)

-> video basics: 720*576 @ 25fps @ 0.6735 (4:3) @ 1698400bps, vbvBuffer 112

dropping useless B-Frames @ GOP#0 / new Timecode 00:00:00.000

video: fr/ct/1p/cg/og/dg 407/1/0/34/0/0

videolength: 407f @ 00:00:16.280

avg. nom. bitrate 856156873bps (min/max: 1504400/2914400)

set first sequence_header bitrate to 2914400bps

===> new File: E:\FTPshare\Music\Video\Radiohead\Les eurockéennes 2003\test\Radiohead - Les Eurockennes 2003 - MPG2HQ.mpv

--> MPEG Audio (0xC0)

Audio PTS: first packet 00:08:00.120, last packet 00:08:15.960

Video PTS: start 1.GOP 00:08:00.160, end last GOP 00:08:16.440

-> adjusting audio at video-timeline

=> src_audio: MPEG-1,Layer2,48000Hz,stereo,256kbps,CRC @ 00:00:00.000

audio frames: wri/pre/skip/ins/add 678/0/0/0/0 @ 00:00:16.272 done..

===> new File: E:\FTPshare\Music\Video\Radiohead\Les eurockéennes 2003\test\Radiohead - Les Eurockennes 2003 - MPG2HQ.mp2

summary of created media files:

.Video: 407 Frames 00:00:16.280 E:\FTPshare\Music\Video\Radiohead\Les eurockéennes 2003\test\Radiohead - Les Eurockennes 2003 - MPG2HQ.mpv

Audio 0: 678 Frames 00:00:16.272 0/0/0/0 E:\FTPshare\Music\Video\Radiohead\Les eurockéennes 2003\test\Radiohead - Les Eurockennes 2003 - MPG2HQ.mp2

=> 4603081 bytes written...

[hms]

I do not think that PVA Strumento will fix this!
PVA Strumento creates a nice "fixed" mpg file that will play synchronized by itself.
But this "fix" will not do for DVD authoring:
Vob files do not alloy that kind of flexibility.
Whatever, do not cut the audio in any way.
Try making a DVD2AVI project (either with the original mpeg file or with the fixed mpg file.
DVD2AVI will indicate the audio delay.
Then its just a matter of encoding and authoring.
But if your video starts out in synch and then progressively gets out of synch more and more then audio must be stretched in order to be synched in DVD (DVD specs do not allow variations in framerate and audio sampling!!!)

[spyder]

Maybe this is not your problem but I had a similar problem with a DVB capture. I found out that for some reason most MPEG Audio decoders b0rk the decoding :/. I have to use madplay most of the time because it seems to work the best so far. Of course, if the stream is broken, there is no way to fix it except find the damaged section and add a delay on the audio from that point on. At worst you would have to reencode the audio.

[Joe_Bloggs]

Clearly WINDVD has a smart mode of operation that the other authors of digital display software have not thought neccessary to invent.
PowerDVD does the same job given the material in my experience. These programs must tap into an error detection and correction ability that are not present in traditional 'ripping' software. There are oppertunities available in the data stream for correcting mistakes.

Fortunately WinDVD codecs and software are an integral component of my subsciption free digital terrestrial receiver card. The displayed picture may be poor due to interference but the recorded picture turns out excellent

I am a big fan of ProjectX by DVBMATT, as it does the business.I think PVAStrumento also deserves investigation as it has been found a worthy alternative in the past. (It does tend to cut material that would be out of sync but salvagable, with a bit of effort)

If your video is out of sync then resync it! I recommend virtualdubmod and a bit of graft. AKA effort.

[Roginator]

Where can one find ProjectX?

[hms]

An unofficial compiled version of projectX you may find at:
http://www.oozoon.de/

[Joe_Bloggs]

Dear Lucius,
I caught your problem at the home page of offeryn (PvaInstrumento)
http://www.offeryn.de/ikonboard/topic.cgi?forum=2&topic=395
Such matters are a commom occurance with digital television recording straight to DVD. Local interferance can mess with sound and video with differing effects. WinDVD does an excellent job but I have also been kept waiting for several minutes while it figures out what is worth playing. This is entirely due to the corrupt data stream that I recorded to harddisk.
PVAStrumento and ProjectX work best by demultiplexing a stream into audio and video. I normally use ProjectX which sorts out the video, then creates a matching sountrack that takes into account the cuts it had to make in the video. Many of these cuts are subliminal but they add up to something in the long run.
The drawback with projectX is that you need the Sun Java runtime libraries to run the program script (a .jar file). If you have the program source code them you need the software development kit aswell (SDK). These are large but free files.
For more information consult:-
http://www.lucike.info/index.htm
There are sections in English and often dual language pages.

The fastest, best and also free multiplexor is BBMPEG. This can stick your video and audio files together after the demultiplexing done by the correction software. If your happy with the playback in ZOOM player then a dumb DVD player will probably play it OK aswell. The excellent ZOOM and BBMPEG are freely available from the doom9 website.

[TerraForce1]

Hi,

I use PVAstrumento latest release. Then I use IfoEdit to author the new DVD. It makes good in sync vob files. If you like you can use a plugin for DVD2SVCD called Roba. It makes an excellent resize of the file. My 2 gig captures are halved that way.

For your information.

[hms]

I also get perfect results with PVAstrumento's latest release and IfoEdit accepts almost any mpeg video and audio file and will author perfectly playable vob files. But Lucius' DVB file may be damaged and therefore more advanced methods are called for.

[Lucius Snow]

Well ... i finnaly gave up with that video. There was nothing to do with it, none method worked. Thanks for your help though :)