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H264/TS, frames lost at cut points

Started by twinsun, July 12, 2016, 10:20:19 AM

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twinsun

Hello, dear ADM team.
I encounter a grrr issue.

> Frames are lost before each cut points of TS, kind below.
The same at end of file.
Adm070716-64 (and before)

Sample : Jeumont.ts 5Mb   (source Iref:4, B:8/24)  https://drive.google.com/file/d/0B7UOzqUbGLumU3ZSOHB1THFPSEE/view?usp=sharing

Edit :      Jeumont ( I-frame 4 to 7 cutting).ts.py  https://drive.google.com/file/d/0B7UOzqUbGLumZXZxdDNBeEU4aVU/view?usp=sharing
              Jeumont ( I-frame 4 to 7 cut done).ts.py  https://drive.google.com/file/d/0B7UOzqUbGLumcnRfYVk0SkNYSk0/view?usp=sharing

Result : Jeumont ( I-frame 4 to 7 cut done).ts 4Mb  https://drive.google.com/file/d/0B7UOzqUbGLumZXdoMWQyLXUxZkk/view?usp=sharing

In copy mode (always cutting at I frames) it is a problem, players freeze the result at cut points.
Obviously, reencoding hides the problem, no freeze. But frames are lost.

Jan Gruuthuse

Preliminary testing confirms there is an issue.
Have the same result on Ubuntu 14.04.4 64-bit (accelerated and none accelerated) with tested with latest build 8fbbf25.

Is this a DVB-T(2) registration? Could be transmission error(s). Developer(s) probably will pick upon this.

mean

This might take a while, it is the worse kind of problems to track down, it could be a lot of thiings

twinsun

Sorry for above sample, not so helpful I guess being itself a cutting.

Ach so... I record a short TS from DVB-T, 13Mb :
https://drive.google.com/file/d/0B7UOzqUbGLumbzhkdWZ6SWx1Mkk/view?usp=sharing

This TS is H264 M:8 N:24
You can verify by yourself that wherever you do a cutting between I frames, the saved result (copy_copy.TS) has the last M, before the cut point(s), with only 3 B-frames, 5 B-frames are dropped. Itââ,¬â,,¢s a travelling sample : ~ all N are 24.

Same way : if you save parts of the video (instead of cutting them), and then append each parts to do a new copy_copy.ts, you have the same dropped at cut points on the result.

In all cases, players freezes at each cut points (evidence).
So you need to re-encode the whole to have a playable video (knowing that you have frames lost at each cut).
ADM copy mode has to be forgotten for these TS  :(.

Personal context : I mainly always re-encode DVB-T TS (4.2.0) to downscale, except in some cases, when the quality source is good enough. Here for example I would re-encode.

Hope it helps this time.

mean

It is actually complicated
The gop is not closed + there are B-Pyramid
I need to rethink it, it cannot cope with that at the moment

mean

It looks like that

I A B C D E F G H

with a display order like this

A B C I D E F G H

and D E F G H need A/B/C to be decoded

At the moment, A, B & C are dropped, as they are in the past, so D/E/F/G/H are not decoded properly




mean