Avidemux Forum

Thanks, Mean and Dosdan!  I'll give that a check ... very cool tool indeed.  I switched to recording AVCHD.  AE doesn't seem to have any problems with MTS files.  And MTS are much better for editing anyway I remembered.

or
1- SD card is to slow to save the video recording, HD or higher resolution, in your (photo)camera.
2- SD card needs formatting in (photo)camera. from time to time some recommend to reformat sd card
3- You are processing video on SD card, always transfer source video to hard disk for editing (never on usb, sd, ...)
4- Batteries in (photo)camera getting to hot. Can't cope with the power drain in video mode.
- ...

Thanks, Jan, however ...

1 -  Card(s) is/are plenty fast enough ... easily exceed many times the required speed.
2 - Could be this.  I did reformat the card as a precaution, even though I switched to MTS files.
3 - No!  I would never do that, lol!  Transferred to a RAID0 array immediately when I get back to my system.
4 - Nope ... not using batteries.  But good thinking!

Thanks again!

-Tim

52de5d5            [core] Bump FFmpeg to 3.3.3
ubuntu HWE 16.04.3 LTS 64 bit x86 SMP, QT5, x265 version 1.9: avidemux 2.7.0 170816-64bit HWE Xenial with x265 version 1.9

Output Format --> Mpeg-PS Muxer( ff)

My first idea was the initial delay incorrectly growing while the total duration remaining the same, thus frames at the end "falling off the cliff". Didn't have time to look deeper into the issue though. This doesn't happen with all videos containing B-frames.

Hi all
I am always trying to understand the best way to cut H264 files without reencoding (audio/video stream copy) with AviDemux.
I think that a key point is to find how the GOP is defined (sequence of I, P, B frames). For that I ve used ffprobe (provided with
ffmpeg package). It gave me relevant informations which are coherent with what AviDemux says, but some questions remain
about the way AviDemux cuts. Below I give more details about what I ve done and what I don't understand.

My intention is to keep the beginning of a movie file (the last part has corrupted data) an to join it later with another file (of the same movie) for which it is the beginning that is corrupted. So to make this as nice possible I would like to cut as close as possible to a scene change and I would like to be able to append something to this cutted file.

To investigate, I work on a short part of the original file, named "all.ts". In a Dos Command windows, I have typed the following command: " ffprobe -select_streams v:0 -show_frames all.ts > all.frames " 
all.frames is thus a text file with informations about frames: There are 834 frames, the first frame is I type. The frames are ordered according to the presentation time stamp (pkt_pts_time); for the sake of simplicity, I call each frame by its order, frame 1, frame 2.. frame 834.
There is also a parameter named "coded_picture_number", which is not at same order than the order of the frame; I suspect this is the order the frame are decoded before  they are shown and it should give some ideas of the dependances between them (I have to investigate more on that point).

I've found a strong scene change with a new scene beginning at frame 347 ( by using AviDemux and checking with DGAVDEc+VirtualDub which allow me to find the time of it and the frame number of this scene change). The sequence of frame around is the following (informations obtained from ffprobe):

Frame   335   336   337   338   339   340   341   342   343   344   345   346   347   348   349
Type             I    B     B     B     B     B     B     B     P     B     B     P     B     B     I

Frame 347 corresponds to time 00:00:14.200 in Avidemux. Frame 1 corresponds to time 00:00:00.400. Besides, the frame types given by AviDemux are strictly identical to that given by ffprobe. Another noticeable thing is the fact that the scene change (frame 347) begins with a B-type Frame, whereas I expected that a new scene would begin with an I-Frame!
To make the cut, I put a [A] label at time  00:00:00.400 (coresponding to frame 1) and a label at time  00:00:14.200 (corresponding to frame 347) and save it (copy mode ) in a file named "cut1.ts".

I hoped a file with 346 frames, as frame 346 is a P-Frame. When analysing cut1.ts with ffprobe (" ffprobe -select_streams v:0 -show_frames cut1.ts > cut1.frames ") I found 335 frames. The first one was the good one (I frame timing at 00:00:00.400 in AviDemux). The last one (335) is an I-Frame, corresponding to what expected (see the table above). This frame should correspond to a timing of  00:00:13.760, but, when loading cut1.ts in AviDemux, it was only be able to show frame up to time 00:00:13.560 and this frame is not reachable.

I made a second try, in which I put a label at time   00:00:13.800 (frame 336), so just after the I-frame 335 and save (copy mode ) in a file named "cut2.ts". The result was the same as for cut1.ts: 335 frames according to ffprobe, and  when loading cut2.ts in AviDemux, it was only be able to show frame up to time 00:00:13.560.

From these trials, I have two points:
1) ending at P-frames seems to be not  possible
2) ending at I-Frames seems not to work completely properly (whereas this I-Frame is an IDR one, labeled key picture according to ffprobe).

Do you have any idea about what happens ? I can put the files on share links.
Thanks a lot for any idea.

Yann