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Old 23rd December 2008, 10:42   #7499  |  Link
madshi
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Join Date: Sep 2006
Posts: 9,140
Quote:
Originally Posted by DrNein View Post
When demuxing an AVC TS, the resolution changes from broadcast standard 1088i to 1084i. Why is that? Is there a way to leave it alone or else change to 1080?
Quote:
Originally Posted by madshi
I've done several checks:

(1) MediaInfo reports 1920x1088 for the original video track. And it reports 1920x1080 for the eac3to processed track.

(2) When playing back the original TS file with the Cyberlink h264 decoder, the video renderer gets 1920x1088 pixels. When playing back the eac3to processed video track with the same decoder, the video renderer gets 1920x1080 pixels.

(3) Same as (2), but with Sonic h264 decoder.

(4) Same as (2), but with ffmpeg/libav h264 decoder.

I think that are enough proofs that eac3to's processing is 100% correct. The cropping down to 1080 from 1088 is a (surprisingly) complicated calculation and tsMuxeR evidently does it in the wrong way. It's so complicated because the cropping size must be multiplied several times, depending on some conditions. E.g. with your sample, eac3to writes a cropping value of "2" into the video bitstream. This must be multipled by 2 twice to get to the correct cropping size of "8". tsMuxeR seems to forget one of the multiplications, that's why it incorrectly reports 1084i instead of 1080i.

Short summary: This is a(nother) bug in tsMuxeR.
Quote:
Originally Posted by DrNein
Well, I suppose that is sort of good news then

Hopefully, tsMuxeR will be corrected for this and a few other things soon (such as 25.01 FPS output and THD handling). In the meantime, do you think it is safe to use tsMuxeR to mux such files? That is, is it only reporting wrong but not altering them?
I don't know. Why do people keep asking me questions about tsMuxeR?

Quote:
Originally Posted by DrNein
Do you plan to add TS and/or M2TS output to eac3to?
No.

Quote:
Originally Posted by DrNein
Also, I have not really noticed any problem with playback of most most 1088 AVC files however 1088 MPEG-2 with DXVA often display a grey bar in MPC-HC but not in PowerDVD. Can eac3to correct those MPEG-2?
No. In MPEG2 it's not as easy as in h264.

Quote:
Originally Posted by DrNein
Is there any potential drawback to eac3to automatically processing to 1080 (with either codec)?
I see none. Actually I think it has several advantages. E.g. with the original file the video renderer actually gets 1088 lines. What will the renderer do with that? Display all of them? Then it must downscale the image, which means we don't have 1:1 pixel mapping, anymore. With the eac3to cropped video bitstream the video renderer is only getting 1080 lines, so we get perfect 1:1 pixel mapping. You can see that for yourself: If you play the original TS file, you'll see some garbage lines at the bottom of the screen. With the eac3to processed stream these garbage lines are gone.
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