How do I avoid recompression?

mekelly wrote on 7/1/2008, 1:16 PM

I have some footage from a Canon HV20 which is 1440x1080 601. I am playing around with the new DVDA 5 and even if I pick MPEG-2 at an aspect ratio of 16:9 and a resolution of 1440x1080 and a frame rate of 29.997 DVDA wants to re-render the video. I have imported native .mt2 files as captured. What am I missing such that DVDA won't want to recompress?

Comments

Wolfgang S. wrote on 7/1/2008, 1:42 PM

The issue is, that m2t is not compatible with the Blu Ray specification - so HDV2 footage will be compressed always.

What you have to do is to encode the HDV2 footage by using the "Blu Ray 1440x1080 60i" template of the mainconcept mpeg2 encoder - that material will not be recompressed at all. For the Audio part, take the AC3 Pro encoder - with the same name in the same folder, then it will be imported in the DVDA5 togehter with the video part (as we had that earlier with the DVDA).

nolonemo wrote on 7/1/2008, 2:07 PM

Wolfgang, if my mt2 out of the camera is 1440x1080 60i at 25mpbs, what's the difference between it and the BD compliant video that has the same parameters?

Wolfgang S. wrote on 7/1/2008, 2:19 PM

Some technical parameter, like the GOP structure or the profile - compare the templates, and you see some difference.

nolonemo wrote on 7/1/2008, 2:28 PM

Thanks. Live and learn, I guess.

MPM wrote on 7/1/2008, 2:50 PM

It doesn't hurt to check out alternative software that might work on/with your streams at sites like videohelp.com...

kitzj0 wrote on 7/1/2008, 4:40 PM

I did what wolfgang suggested and DVD author did not re-encode the video. I have the HV20 and I believe the audio form the HV20 is mpeg audio which is not in the Bluray specs, hence the need for .ac3.

alk3997 wrote on 7/1/2008, 7:28 PM

I'm having the same problem but with any file I try to send to Blu-Ray with DVD-A 5.0. These are all files that do not require re-encoding with Nero 8 (which I started using while waiting for DVD-A 5.0).

The files I've tried are all .ts files and include 1080i, 720p and 480i files. Again all of these do not require recompression with Nero 8 and playback fine on my Blu-Ray player.

Is DVD-A 5.0 broke or am I missing an option somewhere?

Andy

alk3997 wrote on 7/1/2008, 8:09 PM

Answering my own question (hopefully it will help others)...

The part I was missing was that the video and audio must be in separate elementary stream files. If the video and audio are muxed (such as my .ts files) then the video is automatically re-rendered. The funny thing is that the audio is still considered compliant if the video and audio is muxed, just not the video.

I wish Sony would decide compliancy (is that a word?) based on the video stream, not based on the file. Other burning software does (such as the previously mentioned Nero 8).

I assume this is because most DVD-A DVD burning was done with files from Vegas which produces elementary streams when using the Vegas MPEG2 encoder.

Andy

alk3997 wrote on 7/2/2008, 6:43 AM

Picking this up in the thread about ATSC recompression...