[Solved] Save cutting points without reencoding of a dvb HD broadcast

Started by ludi, November 07, 2013, 11:31:59 AM

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ludi

Hi,

I am running Ubuntu 13.10 and installed version 8953 of avidemux by using the following PPA:
https://launchpad.net/~rebuntu16/+archive/avidemux+unofficial

I am using the Qt version of avidemux. (The gtk version does not start on the 64 bit version of Ubuntu 13.10.)

Looking for a way to find the cut points in a ts file recorded from a dvb-s2 broadcast, I was directed to avidemux. However, when I open the file containing 720p material in avidemux and navigate through the frames, it only shows P and B frames. The buttons with two arrows to jump to the I frames seem to work, as it skips frames and stops at a frame not far from the starting point; but the frame it jumps to is indicated as a P frame.

You can find the first 20 MB that I extracted from the 720p file with the linux dd command on rapidshare:
https://rapidshare.com/share/9CBED14909328EAE34F9778EA424A97C?bin=1

The problem also occurs with recorded ts files containing a video track with 1080i.

Could you please make avidemux correctly announce I frames and IDR frames?

Thanks in advance.

mean

Actually it does, that's the problem.
DVB quite ofen uses the following trick : They only use I frame ( never IDR), but with a recovery time of 0
which makes them similar to IDR (but they are not IDR)
Avidemux can navigate both to IDR and almost IDR, but what is reported on screen (P) etc.. is the real type of the image
Non IDR being reported as P frame


ludi

Hi,

Thanks for your reply.

Could you please tell me if I got you right?

- avidemux shows an I for the frame if it is a real IDR frame. But since my file does not contain real IDR frames, it cannot report an I frame.

- The I frames with a recovery time of 0 (whatever this is) are similar to IDR frames in the sense that these frames are appropriate points for cutting without reencoding of dvb broadcasts.

- When I use the buttons with the two arrows in avidemux, it always jumps to a frame that is an appropriate point for cutting without reencoding.

Cheers

mean