Closing the GOP

[Ivan Myles]

AME H.264 export allows you to set the key frame distance, but that does not necessarily mean the GOP will be closed. The first option below will definitely work, the other two options should work provided the GOP only uses one reference frame:

– Key frame distance = 1 (all I-frames, best H.264 quality, larger file), or
– Key frame distance = 2 (IPI GOP), or
– Profile = Baseline (IPPP… GOP, CAVLC encoding)

Have you considered exporting with MPEG-2 instead? It provides more control over GOP structure, and is also the codec used for SD DVD. Your H.264 export is being transcoded to MPEG-2 by DVD Studio Pro.

[Ivan Myles]

You could also use a codec like ProRes, DNxHD, or uncompressed 4:2:2 YUV (very large file size) for better quality. Another option is to create the DVD using Adobe Encore with a Dynamic Link directly to your Premiere Project (no intermediate file required).

[Andrew Johnson]

Thanks for your response. If the GOP is not necessarily closed, then I can’t be sure it’ll work in DVD Studio Pro 4 so it doesn’t really justify waiting for an encode.

I have tried many MPEG2 formats but with those I don’t seem to get any control over the actual Mbps bit rate, just the arbitrary AME 0-100 Quality slider, which is essentially meaningless in terms of DVD Studio Pro 4’s requirements of an actual bit rate.

Am I looking in the wrong places to adjust the output VBR/CBR in AME?

[Andrew Johnson]

Quality is not strictly the issue to be honest, I’m trying to make a multi-angle DVD so I just want a low-ish bitrate file that DVD Studio Pro can encode and that requires control of closing the GOP and the bitrate itself, which AME does not give you. Encore might have to be an option, you’re right. I’m just not sure you can do multi-angle DVDs with Encore…

[Ivan Myles]

[Andrew Johnson] “I have tried many MPEG2 formats but with those I don’t seem to get any control over the actual Mbps bit rate, just the arbitrary AME 0-100 Quality slider, which is essentially meaningless in terms of DVD Studio Pro 4’s requirements of an actual bit rate. Am I looking in the wrong places to adjust the output VBR/CBR in AME?”

AME MPEG2 export parameters are quite extensive. Be sure to scroll down and expand each section to see all the options.

MPEG2-DVD parameters are more limited, but you can still set bitrate and CBR/VBR encoding:

[Andrew Johnson]

Yes, thanks for that, you’re absolutely right. I didn’t check sufficiently those settings—possibly due to near delirium after ouputting this sequence in excess of 50 times without success. The MPEGs are still incompatible with DVD Studio Pro 4 when they are multiplexed and I get video only no audio when I don’t multiplex them.

Encore seems to be the only way forward.

[Ivan Myles]

Have you tried any QuickTime codecs like PNG, JPEG2000, DNxHD, or uncompressed 4:2:2 YUV?

[Andrew Johnson]

No, I presumed all of them would be too big to fit on an SD DVD. Is it the case that I need to start high and let DVD Studio Pro compress it to a low setting? Surely the time factor on that’s going to be a killer.

[Ivan Myles]

[Andrew Johnson] “No, I presumed all of them would be too big to fit on an SD DVD.”

If the file is too big to transfer, try a(n) USB memory stick instead.

[Andrew Johnson] “Is it the case that I need to start high and let DVD Studio Pro compress it to a low setting? “

Yes, it is better to use a low compression intermediate codec if you can’t just rewrap a MPEG2 file without transcoding.

[Andrew Johnson] “Surely the time factor on that’s going to be a killer.”

Actually, H.264 takes longer to encode.

[Ivan Myles] “Have you tried any QuickTime codecs like PNG, JPEG2000, DNxHD, or uncompressed 4:2:2 YUV?”

I just remembered DNxHD is not applicable in this case because it only supports HD resolutions.

[Andrew Johnson]

[Andrew Johnson] “No, I presumed all of them would be too big to fit on an SD DVD.”

If the file is too big to transfer, try a(n) USB memory stick instead.

I’m trying to deliver these files on DVD.

[Andrew Johnson] “Is it the case that I need to start high and let DVD Studio Pro compress it to a low setting? ”

Yes, it is better to use a low compression intermediate codec if you can’t just rewrap a MPEG2 file without transcoding.

But doesn’t that have space implications in terms of how much I can fit on the DVD?

[Andrew Johnson] “Surely the time factor on that’s going to be a killer.”

Actually, H.264 takes longer to encode.

Not in my experience of using CS6 and FCP alongside each other.

[Ivan Myles] “Have you tried any QuickTime codecs like PNG, JPEG2000, DNxHD, or uncompressed 4:2:2 YUV?”

I just remembered DNxHD is not applicable in this case because it only supports HD resolutions.

I am wary of DNxHD due to a right snarl I got into trying to port files in that codec over to edit in FCP, but the other low compression codecs you have suggested are an excellent idea, and thanks again for your response.