Mainconcept producing non-compliant MPEG2 streams?

[mustardman]

Hi,

No info from searching, so here is a question...

I believe the MainConcept encoder is producing non-compliant MPEG-2 streams (ie: DVD encodes).

My source is DV, which I then encoded using the MC MPEG encoder with the "DVD" profile. This was then assembed using DVDlab, and burnt.

If I use a different video stream (either a ripped VOB or an MPG from another encoder) I do not have the problem.

The problem : About every second, and VERY consistently, the image freezes, skips a few frames, and then starts playing again. Like I said, this is very consistant, and does it through the entire clip. It almost looks like the fps is set wrong, but in reverse!

The very interesting thing is that every DVD player I have tried these several different discs on plays them fine, but the only two DVD recorders I tried both gave the exact same problem (different brand recorders).

I am PAL at 25 fps.

Looking at different streams (some which work) using the DVDlab GOP viewer, I can see no difference!

What the hell is going on?

Cheers,
MM

[Arky]

Do you have high bitrates? DVDR can't handle much over 7mbps.

I won't bore you with the details - I and others have posted elsewhere on these forums about why high bitrate causes playback issues with DVDR which are not evident with repicated/pressed discs.

Run your .m2vs (or VOBs) through Bitrate Viewer (http://www.tecoltd.com/bitratev.htm) and check the VBR peaks.

Please report your results and we'll take things from there.


Regards,

Arky ;o)

[ron spencer]

never heard of these problems....I routinely go above 7..never even a hiccup. why would it be a problem...poor media likely to blame. Also what audio is it?

[mustardman]

Thanks for the replies,

I have set my average bitrate to 4.5Mbps, and viewing with the bitrate viewer within DVDlab, it rarely peaks above 7 (even 6).

What I find most strange is that the discs play fine on ALL the players I have tried them in, but will not play properly in both the recorders I have tried them in. I will be going to a few shops today to try the discs in other brands of recorders...

Pressed DVD play fine, and so do DVDs that have been DVDshrunk. The interesting thing is that the problems appear to be with either every single GOP, or with every second one, repeatedly - like the problem is always there, and never seems to disappear or change 'rate'.

Discs that have been created with other encoders (such as the marvellous Pinnacle Studio 8 encoder, sic) do not exhibit this problem, even when using the same media, and the bitrate (the wonderful CBR) set to 8Mbps.

BTW, the audio is fine. Does not miss a beat.

I would be very interested to know if other users of the Mainconcept encoder are experiencing similar problems with playing them in settop DVD recorders.

If the problem does persist, I will have to ditch the MainConcept encoder. Any ideas on good quality alternatives?

MM.

[Arky]

Strange..

1) What media are you using?

2) what speed are you burning?

3) what burner are you using?

4) what audio format are you using? (I presume it is PCM/.wav...)



Arky ;o)

[mustardman]

Sorry for the delay...

1] Princo, DVD-R, 2x
2] 1.2x
3] Sony, but it has no model number on the front, and I don't wish to pull the PC apart to look at the top of the drive. It was basically the first model that could do +R -R +RW & -RW
4] Audio format is MPEG2 (I assume MPEG1 layer 2) at 224kbps (the standard DVD rate). Sampling rate = 48 kHz.

Do you really think the audio format could muck up the video?

I have since tried one of the 'bad' discs on a sony HDD recorder and it works fine. Another JVC HDD recorder had exactly the same problem (I went to a big department store where they had several models on display).

I am only interested in the sony & JVC because they don't need to be put in standby mode to record - two companies that can think to break out of the VCR brainwash!!!

MM

[ron spencer]

well I see 3 problems here.....


1. Princo...avoid at all costs...junk media. I use either TY, Verbatim, or Maxell...never a problem or coaster in 3.5 years...Princo just has caused too many issues on various boards....try some better media.

2. Your burn speed is 1.2? You sure....when it is automatcially chosen this low the media typically is not in the media table in your burner...so it is "doing its best" to burn. What is your burning software?

3. Your audio....while MPEG-2 audio is part of the DVD-spec it was a late edition and I suspect that not all players will play it properly. Here in NTSC land there are a bunch of players that will not play it....my Centrios DVD Recorder for example...so you may want to try AC-3 or PCM to test.

[mustardman]

Thanks for the tips.

I have heard from only one other source that Princo discs are bad, but I have probably burnt over 100 of them (as data discs) without any problems.

As far as speed goes, I am not too sure. I suspect the drive is burning at 2x, but I think the maximum "rated" speed for the drive was somthing stupid like 1.2x or 1.5x (it was a pretty early drive, and is now getting towards 2 years old - arcane in computer land!).

What does concern me is the problem is very regular (every single GOP) and happens with every disc I try (not just the odd one). I might expect odd dropouts with bad discs, but not such a regular problem. I also tried a TDK -RW, and the problem still persists. Also, the (same) problem manifests itself on both a JVC recorder and a Digitrex recorder. A sony recorder, and at least 5 players can play the disc fine!

I strongly suspect the DVD decoder in some of the devices I have tried is either sticking rigidly to the spec, or is interpreting the spec in a different way to most other players.

I have had no problem with MPEG audio, but interestingly I have had problems with PCM ! (from PAL land - I think MPEG was incorporated into the PAL spec, I'm pretty sure AC3 was not, but most players will do it anyway).

Cheers, and thanks for your help.
MM

[ron spencer]

AC-3 and PCM were in the DVD spec from day 1...MPEG audio was later...

well only thing I can suggest then it is a hardware error:

1. Try a different burning package
2. Try different media
3. Try a different burner
4. Try AC-3

If all fail then your recorder is not well for some reason. Have you tried all these options?

[mustardman]

Well, I have finally made some progress.

I discovered, quite by accident, that the problem was being caused by the authoring package!

To verify this (after my suspicions started to rise), I did the following...
. Used a MPEG encoder to convert my DV AVI (and audio) into DVD compliant MPEG-2.
. Authored this single file set (1x audio, 1x video) using two different packages.
. Burned the resulting video onto a DVD-R using the same media, same burner & same burning software.
. Played the results in the problematic device.


This showed the problem.

The problem was with DVDlab - somehow it was making the video jump. I am from PAL land, and since DVDlab is an American product, I suspect that the playing device is initially told to be NTSC (despite the project settings being PAL) when displaying the menus. The video then starts, and the stream is PAL (25fps) but the decoder is trying to work NTSC (30fps).

Interestingly, DVDlab PRO, the other package I tried, does not exibit the problem.

It meant that I could import the entire project, menus and all, and create a working disc from the PRO version (without making any changes). The same video produced with the standard version would not work.

This only also occurred on some players - making the problem really hard to track down. As per usual, the cheaper the player, the less problems. The more expensive, the more problems. Why can't manufacturers of expensive gear get their act together, especially since cheapie gear works!!!!

MM

[Hockey Man]

Mustardman, I was having the same exact problem as you but with dvd-lab pro. Except I made my mpeg2 files with tmpgenc, but still the problem went away as soon as I used a different dvd-authoring program. And its just not PAL either, I use NTSC. Something that is weird though is I dont have this problem when using dvd-lab standard. What was happening to you with dvd-lab is happening to me with dvd-lab pro, what is going on here?

[mustardman]

@Hockey Man

That's really interesting. I was originally using v1.31 of DVDlab to author, and I think I moved to v1.4 something. Both gave me the problem.

I then tried DVDlabPRO v1.00 (an old version, but I happened to have it on disk, and didn't feel like downloading the latest). Anyway, this old version of DVDlabPRO works fine (I tested the finished disc in all the set-top players I had access to).

Perhaps it is a version thing? Maybe one of their updates has introduced this problem?

What versions did you try?

MM

PS: All the versions I tried were demo versions only. I'm hardly going to pay for a product that doesn't work am I !!!!

[Hockey Man]

I tried version 1.00 and 1.5 and they both gave me the same problems. I have a feeling im just gonna have to dump dvd-lab pro, but I need a program that has all the features dvd-lab pro had and I still haven't found one. One of the main things I need from a dvd authoring program that most dont give is the option to add effects to subtitles like shadows and outlines. I would use dvd-lab but it doesn't provide enough functions for me.

[mustardman]

The story gets curiosier and curiosier.

Perhaps it is an issue that causes faults on NTSC playback, but work fine on PAL, when using DVDlabPRO, and vice versa for DVDlab standard.

Since you would really like to retain DVDlab, have you thought about contacting MediaChance?

Cheers,
MM

[Hockey Man]

That could be it maybe. I have contacted mediachance and the guy who replied back said that he didnt know what was wrong :(. It was way back during version 1.0 that I emailed him about it and with every new release the problem still persists.