quenc stutter

[nemo21]

I am having trouble with Quenc and hope someone can help me. I am using quenc 0.51 with DVD rebuilder 0.46. On playback, the video seems to stutter, as if frames were missing. In general, the audio and video are in sync. The stutter is consistent and I don't think it is a normal result of the encoding--it's as if the frame rate were 12 fps rather than 30. This occurs both on playback from the hard drive and from a DVD-R. I have used DVD rebuilder successfully with rejig so I am pretty sure the problem is with the encoder. But I want the quality of quenc! I am using an NEC 2500A (original firmware), XP, DVD decrypter to rip. I've had this problem with several discs, including Pee Wee's Big Adventure, Oz season 2 disc 1, The Lady Eve, etc.

Any suggestions? What should I try to fix this problem?

[Amenophis]

hi, which files have these playback problems? only the m2v by QuEnc, the final re-authored or both of them? Is the source interlaced, and has DVD-RB set the right field order? You could also analyse the video with VirtualDubMod or mme frame-by-frame basis, so you can see if there are realy not enough frames, a couple of identical frames, or just the correct frames in a wrong order.

[nemo21]

>only the m2v by QuEnc, the final re-authored or both of them?

The re-authored VOB files. I do not know how to check the m2v files.

>Is the source interlaced, and has DVD-RB set the right field order?

I believe the source is interlaced. I am ripping with DVD decrypter with the default settings. I am not de-interlacing in DVD-RB.

DVD-RB doesn't, AFAIK, have a setting for field order. I'm not sure how to check to see whether it is setting the right field order.

Sorry to be a newbie on this. I have tried to figure this out just by reading the guides/forums, but I still could use some guidance. Thanks!

[Nic]

How do you play the files? Do you play them in IFO mode (using Media Player Classic or PowerDVD) or do you play just the VOB files?

Seems like a strange question, but it makes a big difference, if you just play the VOB and there's skipping then there is probably an encoding bug, but if it skips in an IFO based play mode, then it means there is a problem normally in the SCR or the way the 2048 blocks are arranged...

Any more detail would help myself and jdobbs track down any possible bug :) Glad you like the combination of our software :) (I still haven't tried rebuilder yet, haven't had the time :( )

Complex but true, ;)
-Nic

[nemo21]

Thanks for the quick response, and yes, I really appreciate your efforts on this software!

I have played the files several ways. I have played them in IFO mode using Media Player Classic. I have also burned the encoded files to a DVD and played it in 2 different stand-alone players. The stutter was the same in each case. I tried buring them onto DVD-RW and DVD-R. Same effect.

I've had this problem on episodic TV DVDs and movie DVDs, and both big and small (Pee Wee is 4.9G=slight compression, Oz was 7.9G=big compression).

I am happy to provide any other details, I'm just not sure what else to tell you.

I have used DVD-RB to successfully encode with ReJig without stuttering, which is why I believe that quenc is the issue. But Oz was unacceptable with rejig. In the opening fight scene of S2E1, there was extreme blockiness and very poor color. Nothing against rejig, of course, but I want a method with better quality if possible.

I do not have CCE to compare against. Feel free to ask me any other questions.

[JDay]

I've had the same problem. It plays fine on 2 players (both Philips) and on PowerDVD. It plays poorly (sound is fine, video is very jerky) on another 2 players (PS2 and Lite-On LVD-2002) and MPC (opening either IFO or VOB). The original m2v played fine on MPC (23.976 fps) but after rebuild (pulldown), it didn't. I've backed up 29.97 fps sources (no pulldown) and they worked fine. The original disc played fine on all tested players, as well as similar discs done with CCE.

[Amenophis]

>The re-authored VOB files. I do not know how to check the m2v files

Most Software DVD Players will play the m2v files, too. i prefer mplayer, which you can get here: ftp://ftp1.mplayerhq.hu/MPlayer/releases/win32-beta/MPlayer-mingw32-1.0pre4.zip

Imho it's nessecairy that you play the m2v files, because it really sounds like an authoring problem (i had something like this in earlier dvd-rb builds). If you want to see a single frame, you can use this too: http://virtualdubmod.sourceforge.net/

>I'm not sure how to check to see whether it is setting the right field order.

you can search for the program 'Restream'. with that, you can check and edit the field order. in general, dvd-rb will set the field order regarding to the source files.

[nemo21]

Thanks for the suggestions so far. Here is an update.

I upgraded to DVD-RB 0.47. I tried quenc 0.51 again. This time, the first VOB of OZ was in sync without stutter. But subsequent VOBs did stutter. Strange.

I checked the .m2v files with mplayer, and these did *not* stutter.

I played all files off my hard drive, so it is not a problem with burning it to DVD.

Any suggestions at this point? Is this an issue with DVD-RB or quenc?

[nemo21]

After my first post in this thread, I got some quick and helpful advice. But no one has replied to my last post for 3 days. Does anyone have any suggestions for me?

I am burning with DVD-RB 0.47 and quenc 0.51. I am getting a video stutter on playback (from the hard drive, DVD-R, and DVD-RW). The m2v files do not stutter. I tried playback on Media Player Classic, an Xbox with DVD upgrade, and a Panasonic standalone.

What can I try next? Thanks for any replies.

[JDay]

I get the stutter on progressive 23.976 content, after DVD-RB does the pulldown. It doesn't seem to do this with interlaced material or when I do the pulldown myself with pulldown.exe. Of course, these same movies, all work fine with DVD-RB using CCE.

Update: I tried a movie that was progressive except for the opening titles. The first 1/4 of the first cell was interlaced, so DVD-RB encoded the cell as interlaced (and apparently flagged the progressive frames as such during rebuild). All the m2vs played fine, but after rebuild only the first cell (even the progressive section) played fine, the rest stuttered.

[JDay]

I tested the same sequence with QuEnc and CCE. The m2vs, of course, played fine. I then ran them through pulldown and both came out fine when only "mark each frame as progressive" was active. If "mark entire sequence as progressive" was activated, both "stuttered". I'm pretty sure this is a QuEnc issue, rather than a rebuilder issue since even when I "sneak" Quenc segments into CCE projects or CCE clips into QuEnc encodes, the QuEnc segments "stutter" and the CCE clips do not. Is is possible that QuEnc is putting info in the flags or the headers on its progressive streams (different than CCE) that might be causing this?

[mean]

You might be interested in merging avidemux patch concerning ffmpeg mpeg2 encoder as it :
- have a better 2 pass max bitrate enforcement
- properly set seq header and pulldown flags for 23.976 stream
(no need to run pulldown afterward)


Just grep PULLDOWN or MEANX in the files that can be obtained here
http://fixounet.free.fr/avidemux/download.html

[JDay]

Hmm... I've found a little hack to "fix" this issue. You can use pulldown.exe to set the prog_seq flags to interlaced, not changing anything else (-nopulldown -framerate 23.976 -prog_seq i). So, it looks like it's related to the prog_seq flag. DVD-RB's pulldown works fine on material encoded as interlaced, and on progressive material, if its flagged as interlaced. Is this a bug with QuEnc or DVD-RB?

[mean]

Yes, it is one of the thing needed to be patched (included in the link i gave above) to have a proper pulldown (-able) stream

[nemo21]

It seems that you two have nailed the problem--is this now a known bug in quenc?

I looked at these other programs but the whole reason I tried DVD-RB is that I'm looking for a one-click windows solution that doesn't require me to learn stuff requiring a command line program :)

I thought that more recent versions of DVD-RB would solve the problem but it still exists in 0.49

[mean]

The bug is from libavcodec that does not support pulldowned mpeg2
which is kinda hybrid between progressive and interlaced.

I've added a new MPEG2_PULLDOWN flag to avcontext so that it correctly set the progressive/interlaced flags, set the fps and set rff/tff flags

Since it is not a huge patch, the simpler may be to merge it into qenc

[Nic]

Forgot about looking into them, thanks mean. I'll do that :)

-Nic

[dragongodz]

sorry but i have to correct this major misconception.

IT IS NOT A BUG IN QUENC OR LIBAVCODEC.

first read this to understand what pulldown is actually doing.
http://www.doom9.org/synch.htm

right now that you have done that you should understand that if anything the bug is in the pulldown. it should take the progressive frames and make them, or treat them at least as, field based for the telicining. you should NOT have to make the stream pretend to be interlaced when its not. infact it should be left alone if you are outputing non telecined anyway such as progressive PAL 25fps or true 29.97fps stream or an mpeg that you really want to keep as 24fps.

so Nic if you are going to add that please make it an option rather than always on.

[mean]

In case of pulldowned stream the seq header says it is interlaced
where each picture is progressive (from memory)
+ you have to alter the rff/tff flags and change the FPS in the seq header to 29.96 but keep a timestamp based on 23.976

Only in the case of pulldowned stream.

It is not a bug per se, but a lacking feature i.e. the ability to specify the stream is pulldowned to be able to use for DVD or SVCD.

As said earlier, this is an extra flag to set in avcontext, you set it or not depending on what you want

It does NEVER alter the frame progressive flag, just the seq_header flags.

[dragongodz]

It is not a bug per se
no its not a bug at all, no "per se" about it, yet thats what people kept saying here. :)

a lacking feature
yes a lacking option i accept. it could easily be argued its a lacking option of DVD-RB aswell though. :D

[mean]

No, a lacking feature by itself
With the patch and if you set the the PULLDOWN flag you have a mpeg2 ES suitable to SVCD or DVD without the need for any external tool
, except a muxer if qenc does not include one.

[dragongodz]

No, a lacking feature by itself
a feature, an option, picking over semantics ????? :)

With the patch and if you set the the PULLDOWN flag you have a mpeg2 ES suitable to SVCD or DVD without the need for any external tool
you make it sound as if QuEnc cant produce an ES suitable for SVCD/DVD without it and thats simply wrong. you can encode progressive at correct fps or encode interlaced and use pulldown currently which are both suitable. so the ability to use a progressive ES with interlaced seq_header flags is just another option/feature. one which will probably be added anyway thanks to what you have posted.

without the need for any external tool
, except a muxer if qenc does not include one.
no QuEnc doesnt mux it just encodes the video. what WOULD be interesting is to know if any other programs require the seq_header flags aswell since this has only come up so far with DVD-RB. so do other authoring programs require it aswell or do they correct it themselves ? if anyone tests this can they post their finding here ?