MPEG-2 and MPEG-4 compression issues with Compressor

[Tim Ryan]

I was able to create an MPEG-4 version via Quick Time Conversion vs. Compressor. Not sure why this worked and compressor does not now work? The compressed MPEG-4 looks mediocre.

I applied the following steps:
-Export to QT Conversion
-File Format = MP4
-Video Format = MPEG-4 Improved
-Date Rate = 256
-Size = 320×240 GVGA
-Frame Rate = 29.97
-Key Frame = 24 Frames

It’s 39 Mb.

[Tim Ryan]

I just cleaned out the Compressor preferences and the MPEG-4 compression worked via Compressor. Will now test the MPEG-2.

[Tim Ryan]

Well, the MPEG-4 compressed through Compressor did not “fail” but it has the same issue I had with the MPEG-2 compression through Compressor. One of the segments within the project is frozen on its first frame. That may not technically be the best way to describe it. It’s a map with a moving red line that corresponds with a driving tour of a neighborhood. As we drive through the neighborhood, the red line moves along a map. The map is a .mov file.

Again, I was able to compress an MPEG-4 as an export to Quick Time conversion. It doesn’t look as good as the Compressor version but the line moves within the map.

Thanks for any advice.

[Don Greening]

It could be a corrupt FCP render file that Compressor doesn’t like. If an encode insists on stalling, crashing or otherwise has encoding issues at the same spot each time, then it can usually be attributed to something that’s corrupt in the one spot. It may be faster to simply trash all the render files for that sequence and allow FCP to re-render everything. If you can pull up Comppressor’s encoding log it may also tell you something. I know that in DVD Studio Pro you can read the DVD log when it burns to disc and there’s an issue that makes it crash. The last thing in the log before the crash is the problem.

Hope this helps.

– Don

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[Lee Burrows]

I agree with Don. You might also try make self-contained FCP reference file and then bring that into compressor. This will pull all the information together so that it hopefully helps alleviate this problem.

I know that when I add Boris transitions to a project in FCP and then run it straight through compressor without making a self-contained FCP reference file then I get freeze frames where my Boris transition was supposed to be but if I make the self-contained FCP reference file then the transition works perfectly. I got the advice fro the pros on this great website. To make a reference file then go to export and shoose quicktime movie then uncheck the box labeled make self contained movie or you can make a self contained movie. It really doesn’t matter. It is just a space issue. A reference file is a lot smaller.

Hope this helps

Lee

G5 Mac OS X
Dual 2.0 GHz
FCP 4.5 HD
XServe Raid 1 Terabyte

G5 Mac OS X
Dual 2.3 GHz
FCP 5.02 Studio
G-Tech G Raid 500 GBs
2 – Lacie Drives 200 GBs

[Tim Ryan]

Lee and Don,
Thank you both for your advice. I’m always afraid to trash files in the middle of a large project so I chickened out and opted to first try to create a self-contained reference file. This seems to have worked perfectly. I exported the new file via Compressor and tested both MPEG-4 and MPEG-2. They both worked and actually look better than ever.

What exactly happens when you create the self-contained reference file that makes this work? Is this something that is recommended prior to creating a final MPEG version of the project for DVD? Are there any other things I should do prior to the final output?

Thanks again!

Tim

[Lee Burrows]

Hey tim. I’m glad that worked for you. I don’t know all of the technical jargon that goes along with how it works. However what I believe happens is imagine your FCP timeline is a pile of trash that is all paper with one or two pieces of leftover food(this might not be the best image but bear with me:) spread across the floor. It is all in order to be collected but in order to be collected it needs to be bagged. Bagging it or making a self contained movie puts everything into its proper alignment so that it can now be taken to get dumped properly or compressed via compressor. Oh well…I tried:)

In technical terms I believe it has to do with the GOP(Group of Pictures) structure and when you introduce something out of the ordinary into your FCP timeline GOP structure it confuses compressor so when you export it as a reference file or self contained movie then it redoes the GOP structure to group everything together thus eliminating the confusion for compressor.

I had an HDV FCP timeline that I was trying to master back to my HDV deck. It wouldn’t get 30 seconds into the timeline before dropping a frame. I was frustrated about this for days as I captured it fine from the deck but it wouldn’t export back to the deck without freezing up/dropping a frame. Finally after talking to the people at Sony they told me to export my timeline via quicktime conversion with the HDV codec, then import that file and then play it out of an FCP timeline. WAALAA…it worked like a charm. The same thing was happening to me that was to you. The GOP structure to export to tape was breaking up with all the files as separate parts but when I did the conversion which regrouped everything together it played like a charm to tape.

To answer your final question is no you shouldn’t need to do anything else differently depending on how you are mastering your final output.

Were you that impressed with the final mpeg2? Do you think that it looked better after making the self contained movie then before when you went straight through compressor? It shouldn’t improve the quality but never say never.

That’s my two cents.

Good Luck

Lee

G5 Mac OS X
Dual 2.0 GHz
FCP 4.5 HD
XServe Raid 1 Terabyte

G5 Mac OS X
Dual 2.3 GHz
FCP 5.02 Studio
G-Tech G Raid 500 GBs
2 – Lacie Drives 200 GBs