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Compression Master incompatible MPEG???

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tgw108
Compression Master incompatible MPEG???
on Sep 12, 2006 at 6:51:24 pm

I am having a weird issue with a particular DVD I authored. The DVD contains a simple motion menu and track. The motion menu and track are both widescreen. I encoded both assets using Compression Master 4.0.2. Imported into Dvd Studio Pro and made a DVD. Now on one player, the Panasonic PV-D4745S, the video wont play. These are replicated discs, so disc media isn't a factor. Only the overlay on my motion menu shows up.

Is this an issue with the MPEG's not being universally compatible? It works in all other players I've tried. This is a high profile project, so any help would be appreciated.

Thanks,
Tom



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Charles Simonson
Re: Compression Master incompatible MPEG???
on Sep 12, 2006 at 7:51:05 pm

I have run across an issue where motion menus don't always play back the same on various DVD players and discs authored in DVD SP. Not saying that it is not a CM issue, but if DVD SP accepted the asset and didn't throw a fit or give you a warning upon build, then I am less inclined to believe it is an encoded asset issue. Although CM has had some issues with importing encodes into DVD SP, that should have been addressed in the recent build you're using. Previously, DVD SP wouldn't even accept the encoded stream if there was an issue.

What were the specs of your encoded assets, both video and audio? I have a couple of Pany players. If you want to upload a short clip that I could burn and test I would let you know how it goes.


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tgw108
Re: Compression Master incompatible MPEG???
on Sep 13, 2006 at 1:50:07 pm

That would be great Charles. I haven't elminated DVD SP as the culprit, but I suspect Compression Master first because of a few things...

1. If I skip the menu, and set the first play to the track, the main video still doesn't play
2. The audio does play
3. The overlay on the motion menu does play.

So it appears to me that the only thing that doesn't play is the m2v. Again we are talking about only one player at the moment. Everywhere else I tested is fine.

Here are links to the menu assets.
http://wpsx.psu.edu/storage/menu.zip

I encoded the video in Compressions Master using the m2v_MPEG2_NTSC-5Mbit setting with 2 changes.

1. I bumped the bit rate to 6.5
2. Changed the apsect ratio to 16 by 9

I encoded the audio via Compressor 192 Kbps Dolby AC3




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tgw108
Re: Compression Master incompatible MPEG???
on Sep 13, 2006 at 4:25:33 pm

Further evidence of it being a Compression Master issue....

I encoded the same footage via Compressor and it plays fine in the offending player. Any ideas on what was wrong with the Compression Master encode?

(see settings in previous post)

Thanks,
Tom



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Charles Simonson
Re: Compression Master incompatible MPEG???
on Sep 13, 2006 at 5:31:06 pm

I can analyze the encoded streams if you wish with some MPEG-2 analysis tools that I have. That would be the best way to determine this. If I have time tonight, I will check it out. Also, I would say that the MPEG-2 encoders in Compressor 2 and CM 4 are about on the same quality level, so if you need to get something done soon, I would suggest using Compressor for now. The only real benefits CM offers for MPEG-2 encoding over Compressor at this time is better and faster batch encoding as well as some custom MPEG-2 output format options. Speaking of which, in CM, you didn't enable the 4:2:2 color space for encoding did you? I doubt you did, but it should be noted that 4:2:0 is the only color format 100% compatible with DVD.


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tgw108
Re: Compression Master incompatible MPEG???
on Sep 13, 2006 at 5:43:55 pm

Great thanks! If you have analysis tools that are available to us normal folks, I would love to know where to get them.

Unfortunately these dics have already been replicated. I didnt have this Panasonic player to test with prior to the replication. I am, in general, very interested in using the best tools/encoding methods for compatability across DVD players. I think I already follow the general best practices guidelines, which is why I am disappointed that this Compression Master encode had problems.

Nope, I didnt change the color space.

Thanks again,
Tom



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Charles Simonson
Re: Compression Master incompatible MPEG???
on Sep 14, 2006 at 6:52:36 am

Well, the first tool I like to use just to get general info is MPEG StreamClip. It is free. The second is Digigami MPressionist. It costs moola but is very valuable if you are doing lots of MPEG-2 encoding and I highly recommend it. I have other tools for MPEG-2 IP streaming and VC-1 and H.264, but they are PC apps.

Now, to the encode you linked to: I did have a problem with it using a burned DVD-RW (2x) and a DVD-R (4x) in my Pany. My other DVD player did play it fine, but it has a very robust chip decoder that can pretty much play back all MPEG-2s. Looking over the encode in MPressionist, the only thing that I could quickly determine is that the encode's bit rate spikes around 10Mbps at the beginning and then settles to lower than 1Mbps for the remainder of the clip. The low bit rate can be attributed to the still frame image (the clip's length also has something to do with it) that is being encoded so it is understandable why that is. But the spikes above 10 could possibly be too much for the Pany's decoder, or the low level of the bitrate could be an issue as well. The DVD spec suggests that to ensure reliabilty that an encode can only go to 9800Kbps I believe (I have found that it also helps to make sure the encode never dips below 1900 Kbps). I may be a little off on those numbers, but the gist of it is that your encode violates those parameters.

I could do further analysis, but I would need the Compressor encode that you did to compare against for better understanding.


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tgw108
Re: Compression Master incompatible MPEG???
on Sep 14, 2006 at 12:53:42 pm

Thanks for checking Charles, that was helpful.

Hmmm... well I knew of these requirements, but I have to trust my software. I set the target bitrate to 6.5 and the max at 7.5. I would not have expected dips that low or that high. Is this a known issue in Compression Master?



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Charles Simonson
Re: Compression Master incompatible MPEG???
on Sep 14, 2006 at 4:28:31 pm

Well I think those spikes are not that unusual for the beginning of the clip and I don't think they extended over the amount of acceptable buffer time. So I am not 100% sure that that was the issue. But going off of what I had available to me, it was the only thing I come up with. If you could upload a sample (preferably a new clip for each but one with some action in it) of a Compressor encode that works and a CM encode that doesn't, that would help greatly.


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tgw108
Re: Compression Master incompatible MPEG???
on Sep 14, 2006 at 10:28:35 pm

Ok, here is a zip file containing two new clips. The Compressor version (SOU_TEST_COMP.m2v) works, the Compression Master version (SOU_TEST_CM.m2v) does not.

http://wpsx.psu.edu/storage/test.zip

Again we are only talking about the Panasonic players. It works in all others I tested.

These are 20 seconds of action shots, not sure if you need more. Thanks for all your help with this... You are welcome to tell me to shove off at some point.

Thanks again,
Tom



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