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Hagop Goudsouzian
ame mpeg2 vs mpeg2-dvd
on Apr 5, 2013 at 12:31:57 am

As some do not have a Blu-ray player, I am compressing for dvd. I have used other compressors for dvd but not ame cs6. I noticed there are 2 mpeg2 settings "mpeg2" and "mpeg2-dvd", they both seem dvd compliant. My source file is prores422 1080i. When I do a test "mpeg2-dvd" of 3min. the output is m2v 720x404, but it has black edges on the right and left of frame. Whereas if I use "mpeg2" with similar settings as "mpeg2-dvd" I can resize it proportionally giving 720x405 without the black edges on the left and right, extension mpg. The quality is superior in mpeg2-dvd but the thin black edges on left and right is confusing me. Yet when I view it with QT the frame size is 720x404. (Apples's Compressor does not have these black edges.)

In addition, when I spot check frames, there is a discrepancy of two frames by the time I reach about 2m05s as compared to Apple's "compressor." will I have syncing problems?

I have not watched it on a dvd yet as I am still testing. Should I be concerned about these black bars or can i get rid of them with a setting?

Thanks,

Hagop


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Jeff Pulera
Re: ame mpeg2 vs mpeg2-dvd
on Apr 5, 2013 at 3:04:13 pm

Hi Hagop,

Definitely use "MPEG-2 DVD", as there are differences and your file needs to be "DVD compliant". If not, then Encore will need to transcode it (recompress again).

Do not trust what QT says about frame sizes (I have seen many posts about that recently). If you encode using the "MPEG-2 DVD" preset, it should always come out at 720x480 for DVD spec, and nothing else!

The reason you are getting the slim black bars on the output is because the math for the downconversion from HD to SD doesn't come out quite right. In AME, under OUTPUT tab, change "Scale to Fit" to "Scale to Fill" and this will remove black side bars.

The .m2v format is correct for Encore. The audio will be .wav (on PC) and Encore quickly converts this to Dolby .ac3 and the video is already compliant for DVD and it ready to burn. If you create an .mpg file, the audio and video are combined, with audio compressed as mpeg, so then Encore needs to separate audio and video and recompress again to .ac3, not desirable!

Thank you

Jeff Pulera
Safe Harbor Computers


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Paul Stevenson
Re: ame mpeg2 vs mpeg2-dvd
on Apr 5, 2013 at 4:06:47 pm

720x480 is correct for NTSC, not for PAL, just putting that out there in case it makes a difference to your black bars.


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Hagop Goudsouzian
Re: ame mpeg2 vs mpeg2-dvd
on Apr 5, 2013 at 5:38:58 pm

Thanks Jeff,

I did a side by side test previewing with both Apple's Compressor and AME, using exact same frame.
I chose a default setting with Compressor, and I see no cropping, comparing source vs compressed.
I chose a default setting with AME (mpeg2-DVD) when I select, "Scale to Fit" I get the slim black bars.
But when I choose in AME "Scale to Fill" I do not get the slim black bars but the image is cropped top and bottom.
I do't know if Compressor is imperceptibly altering the image but seems true to source.

Maybe I am missing something, source is 1080 interlaced NTSC.

Any thoughts?

Thanks,

Hagop


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Jeff Pulera
Re: ame mpeg2 vs mpeg2-dvd
on Apr 5, 2013 at 5:47:51 pm

I can't comment on Compressor, am a PC user. However, I actually don't worry about the black bars myself and encode as-is, figuring the black area will not be viewable on most displays, being in the overscan area.

Adobe didn't used to create the black bars, but the BBC is a big customer and apparently prodded Adobe into changing the aspect ratio for SD widescreen, which now results in the downscale from HD to SD not coming out quite right without additional work.

Just Google "adobe pixel aspect ratio change bbc"

Thanks

Jeff Pulera
Safe Harbor Computers


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Hagop Goudsouzian
Re: ame mpeg2 vs mpeg2-dvd
on Apr 5, 2013 at 5:58:07 pm

I'll go ahead with default and slim side bars. The oversan does make sense, I'll see what happens.

Now it is coming back to me! I did do some similar tests a few years back, then abandoned AME for DVD and used Apple (without probing further,) but my recent experiences encoding for Blu-ray were great so I thought I give it a try for DVD. Very nice!!!

Thanks Jeff for your advice, appreciated.

Hagop


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