DV-AVI -> TMPGenc -> DVD. Skips in movie

[michelmichel]

I convert a dv-avi to mpeg2 using TMPGEnc.

When using the SVCD/PAL template, the video is fluent and everyting is good.

When using the DVD/PAL template, there are lots of skips in the video.

What should I do to solve the problem?

Thank you in advance.

[DJRumpy]

michelmichel, did you change any of the default settings on the template in TMPGenc? Also, does it skip on both your PC, and your DVD player, or just one of them?

[michelmichel]

Hello DJRumpy, thank you for answering.

I did not change anything to the DVD template, and I got these skips in the movie.

For further tests, I also tried the settings according to this guide: http://dvd-hq.info/Compression.html
It gave exactly the same result: skips in the movie.

I can't understant why everything is perfect with the SVCD template, but not with the DVD template...

The skips appear on my PC (viewing with Windows Media Player, as well as in Windvd after an image of the DVD is made with IfoEdit. In both cases, the skips appear exacly at the same place).

I did not try on a standalone DVD player. Is it possible the skips only appear on my PC and not on a DVD player?

I do not think about a CPU speed problem on my PC, because
- skips appaer always at the same place on the movie
- my PC is quite powerfull (P4)
- the original DV-AvI file is read without any skips on my PC.

Do you have any idea?

I am looking on various forums about that, but I don't find anything related to that problem.

THANK YOU

Michel

[DJRumpy]

If the skips appear on your pc, and always in the same place, it could still be a PC issue. Not likely with a P4, but possible. An easy test would be to drop the video on another PC. Full DVD resolution video isn't exactly easy. The video card also plays a large part in reproducing it. If playing it on another PC isn't an option, then I would next consider using an RW format. Unfortunately, RW is supported mostly on the newer standalone players. You should check to see if yours supports DVD-RW/+RW in the DVD Players section of this site. This would allow you to burn without fear of making a coaster.

Can you describe the skips in more detail? Does the audio lose sync?

[michelmichel]

I can not easily try on another PC and... describing the skip is not so easy... I would say that the movie stops for a fraction of a second and then starts again but with a loss of image. But I do not have any audio lose sync: the sound is good (no skips).
Would you accept that I send to your email a small sequence (1500 KB) with the problem?
Thank you.
Michel
(michel underscore saintrain at hotmail dot com)

[DJRumpy]

It almost sounds like a buffer overrun, or underrun. Curious that the audio didn't lose sync though.

Did you enable padding in TMPGenc? I'm assuming you use VBR for your DVD. Go into the Setting button for the Rate Control Mode, and check the 'enable padding' option. Some players have a problem with low bitrate. That option may help. Set your MIN setting to anything above 300. Another easy way to test is to simply try a small CBR encode to see if the problem lies in the bitrate of your DVD.

I would suspect a bad source, since the skips are in the same place, but the fact that SVCD seems to be fine would seem to eliminate that. Just because your source appears to be fine, doesn't eliminate the source as a potential source of the problem. If an encoder encounters a bad frame(s) in a source file, it simply skips them, or fails trying to encode them, causing a blip in your mpeg. It can cause loss of audio sync. Huge colored blocks to appear, all sorts of wierdness. All with a a source file that appears pristine.

Bye the bye..what Video Bitrate, and Audio Bitrate settings are you using? Also, what field order, and what is your source video file from (ie. DVD, CAM, Capture, etc). Last but not least, are these skips at regular intervals?

[michelmichel]

I tried both CBR and VBR, with the same (poor) result! In VBR, I also tried your setting (enable padding not to be lower than... Min=750). It did not help.
My source (PAL DV-AVI) looks really very good and fluent... Anyway, is there a software I could use to verify i hasn't bad frames?
My settings (among others) are:
CBR video 8000 kbps audio m2p 384 kbps stereo
or
VBR video average 5000, max 7000, min 2000, 2 pass, enable padding not to be lower thatn 1000 (no audio)
My source is a MiniDV camcorder, transformed with Movie Maker 2 and saved to dv-avi.
Are the skips at regular intervals? I would say YES. About once per second.
Thank you for your help.

[michelmichel]

Sorry, the skips are about one per 1/2 second (more or less)...

[DJRumpy]

I wonder if somewhere along the way, the framerate is being changed? Can you confirm the framerate in both the source, and the output AVI?

[michelmichel]

Yes. Unchanged at 25 fps.
Before checking further in TMPGEnc, quality of AVI source etc., I think what I should do is to burn a disk and try on a standalone player + TV. I will do that this WE or next week.
See you.
Michel

[michelmichel]

Hello DJRumpy,

I tried on a standalone player connected to a TV. Same result, even worse:

- "skips" in the movie (they look even more ugly than on a PC)
- also "skips" in the audio, at the same time as the skips in the movie (while on a PC the audio is correct!).

There are about 100 skips in a minute, so, about 1 skip fot each 6/10 of a second. The intervals between skips are very regular.

This test was made using the standard DVD PAL template of TMPGenc (ver. 2.510). On PC, I made other tests with the other DVD templates of TMPGEnc, with the same poor result.

The same movie encoded with the SVCD PAL template is perfectly fluent, both on PC and on TV.

What is your opinion about that?

Thank you.

Michel

[DJRumpy]

If the skips are this regular, then it sound likes a frame being dropped. Load the MPEG into VirtualDub (MPEG), and step through the frames one at a time. Look at how the motion skips. See if it goes foward, and then steps back, or it simply jerks foward. Also, please verify the framerate of your input DV file.

[michelmichel]

OK, I will try that. I am not a user of virtual dub. I just installed it right now following your post. It can not open my avi file (can't locate decompressor) nor my mpeg file (can read mpeg2...). I will look further to understand how to use it.

By the way, I looked at all differences between the SVCD and DVD templates of TMPGEnc and found that there are few. I tried to set all settings of the DVD template to their value in the SVCD template (VBV buffer, DC, GOP, etc.) without any improvement (keeping the bitrate and resolution of DVD of course): still the "skips".

Other tests, more interesting:
- In the DVD template, I reduced the bitrate to about 2000 Kbs. Good result: the skips are not present anymore.
- In the SVCD template, I increased the bitrate to about 8000 Kbs. The skips are appearing!

So, it seems that the problem is strictly related to the bitrate setting: no skips with low bitrates; skips with high bitrates.

Is this a usefull indication to search the solution? Is there somewhere (in TMPGEnc or in WinXP a setting for memory buffer or anything else related to that, ...)?

Thank you.

Michel

[DJRumpy]

There is a specific version of VirtualDub to open MPEG-2. You can find it here: http://es.geocities.com/dextstuff/#VirtualDub

On your bitrate settings, which bitrate setting are you changing, and what type of MPEG-2 are you creating? VBR, or CBR. If it's VBR, are you modifying the Min, Avg, or Max setting to reproduce these skips?

[michelmichel]

1) I opened my movie.m2v file in VirtualDuB. VirtualDub says it opens an mpeg1 file (though it is a mpeg2 file!). Then I "play" it frame by frame with the "next" key. It plays fluently. I DO NOT SEE THE SKIPS (but there is a sort of interlace effect).

??????????

2) About my bitrates settings: I have used CBR in the last test. The bitrate I change is, of course, the video bitrate.

[DJRumpy]

Does this 'interlace affect' have a pattern? Something like 3 progressive and two interlaced frames?

Also, what did VirtualDub report for framerate on your source MPEG?

[michelmichel]

All frames seems to be interlaced. VirtualDub reports 25.000 fps. It plays witout skips.

When I save that file to avi in VirtualDub and then load the avi again in VirtualDub, VirtualDub plays it at a frame rate of about 11 fps (half speed). Is it normal?

[DJRumpy]

Most definately not. Make sure you don't select any special options when opening the file in VirtualDub. Also make sure all options are off on the VIDEO | FRAME RATE menu (No Change / Process All Frames / None )

In TMPGenc, I would skip the wizard, and go into the Settings button.

For the VIDEO tab:

Stream Type: MPEG-2 Video
Size: 720x576
Aspect Ratio: 4:3 Display
Frame Rate: 25fps
Rate Control Mode: Constant Quality (CQ) (easier to test with)
VBV Buffer Size: 0 (automatic)
Profile & Level: MP@ML
Video Format: PAL
Encode Mode: Interlace
YUV format: 4:2:0
DC Component Precision: 10 Bits
Motion Search Precision: Motion estimate search (change this if you get macroblocking on high motion scenese)

For the ADVANCED tab:

Video Source Type: Interlace
Field Order: Bottom Field First
Source Aspect Ratio: 4:3 625 line (PAL)
Video Arrange Method: Full Screen (keep aspect ratio)

Disable all filters (checkboxes) under the ADVANCED section

For the GOP STRUCTURE tab:

Number of I picture in GOP: 1
Number of P picture in GOP: 4
Number of B picture in GOP: 2
Output interval of sequence header: 0
Output bitstream for edit (closed gop): Unchecked
Detect Scene Change: Checked
Force picture type: Unchecked

Under the QUANTIZE MATRIX tab:

Select the 'Default' matrix from the drop down list
Output YUV data as Basic YCbCr not CCIR601: Unchecked
No motion search for still picture part by half pixel: Unchecked
Soften Block Noise: Unchecked

Set the audio to your preferences (usualy around 224 kbits/sec)

[michelmichel]

1) I tried your settings. The skips are still there (viewing on PC).

2) In VirtualDub:

When loading the mpeg2 file In VirtualDub, a message says "parsing mpeg1...". Is it normal?

VD reports 25 fps.

The "preview" displays the movie without any skips, but with interlace effect (comb) while this effect does not appear with other players. Why?

I save the file to avi in VD (save as avi) and load it again. VD reports 25 fps, but plays the file (preview) at a bitrate bitween 8 en 10. Normal?
I confirm all options in the frame rate menu are off.

At the end, should I conclude that my mpeg2 file is OK or not?

Is it possible that the "skips" on the standalone player would have nothing to do with the skips on PC? I mean, that they would have a different origin? Why do I have skips on both movie and audio on a standalone player, and only skips in movie on PC?

Thank you !

[DJRumpy]

When loading the mpeg2 file In VirtualDub, a message says "parsing mpeg1...". Is it normal?

Yes. The VirtualDub MPEG modification is just a modified version of VirtualDub. VirtualDub (the original) only supported MPEG-1. Don't worry about the MPEG-1 Prompt.

The "preview" displays the movie without any skips, but with interlace effect (comb) while this effect does not appear with other players. Why?

Many players compensate for interlacing by either de-interlacing, or frame doubling the movie on playback. VirtualDub just shows it 'as is'.

I save the file to avi in VD (save as avi) and load it again. VD reports 25 fps, but plays the file (preview) at a bitrate bitween 8 en 10. Normal?
I confirm all options in the frame rate menu are off.

I assume you mean it reports a framerate on the saved file at 8 or 10fps? Definately not normal. If the saved file has a drastically different frame rate than your source, and you are not modifying any of the settings with VirtualDub, then I would guess that teh MPEG file is corrupt/bad.

[michelmichel]

I assume you mean it reports a framerate on the saved file at 8 or 10fps? Definately not normal. If the saved file has a drastically different frame rate than your source, and you are not modifying any of the settings with VirtualDub, then I would guess that teh MPEG file is corrupt/bad.

No, I mean that, when I load the saved avi file, then in "File information" it reports 25.000 fps (as expected). But when previewing the file (F5 or "preview") the video rendering rate is about 10 fps. Is it normal?

[DJRumpy]

That would jus depend on your PC's peformance, the filters enabled, etc. Playback speed for preview isn't indicative of a bad/corrupt MPEG.

[michelmichel]

OK. Is the conclusion of this all that my MPEG2 is correct?

And what is than the reason of the jerks?

[DJRumpy]

At this point I'm out of ideas. You've already said that SVCD plays fine. DVD skips. The output rate of DVD and SVCD mpegs are both still 25fps (you verfied with MPEG Properties?).

DVD skips only on higher bitrate. Is all of this correct?

[michelmichel]

At this point I'm out of ideas. You've already said that SVCD plays fine. DVD skips. The output rate of DVD and SVCD mpegs are both still 25fps. DVD skips only on higher bitrate. Is all of this correct?

Yes, correct. I still imagine on other hypothesis: lets suppose that the jerk on PC are due to lack of resources while the jerk on TV is due to lack of comptabibility (media type, ...). So, jerks in both cases, but different reasons. Is this possible? I will make other tests on standalone player (other media, other bitrates, etc.)

(you verfied with MPEG Properties?)

What do you mean????

By the way, I would like to thank you for your help about this. I greatly appreciate that people like you spend of their time to help beginners like me... That's great.

[DJRumpy]

It's a tool in the TOOLS section. Very handy to look at the properties of any MPEG file. The Windows OS doesn't have any handy Right-Click properties for MPEG. This tool will report Bitrate, Resolution, and Framerate. Handy to have, as sometimes you need to verify these things in an MPEG file.