Hi, I have a problem that I suppose most people don't have because I have "broken" the file I need fixed myself.
The problem is I have a series of flv files dumped with rtmpdump that I want to merge, which have identical video/audio streams with overlap so they can't simply be connected one after the other. (That is for example file1 goes from 0-1hr file2 goes 45mins to 2 hours, etc) I have linux so I am unable to try most of the merging tools I found with a google search, but avconv and ffdshow both seem to be unable to do it.
The files all have identical video/audio streams and since they overlap I went and found a spot they are the same in a hex editor and simply used dd to trim them then cat to join them together. Once concatenated together the playback is perfect and seamless in the version of mplayer2 I have installed (2.1~git20120828.28228-1) from start to end, however it doesn't show total play time and the OSD time jumps backwards when it hits the join point in the files with the message:
Code:
Decreasing video pts: 4.743000 < 50.986000
Playing the same file in VLC causes a large skip, presumably VLC is skipping ahead to the next point in the file where the pts is greater than the last one it played.
I was hoping these concatenated files could simply be run through ffmpeg with '-codec copy' but when ffmpeg (most recent compiled from their git) gets to the join it gives a series of errors like this:
Code:
[flv @ 0x204cba0] st:0 PTS: 41471 DTS: 41471 < 50991 invalid, clipping
The resulting file has the wrong total time, and when it gets to the join the video skips ahead a fair bit (in mplayer2) then the video ends early while the audio continues to play without any skip and goes its full length. VLC behaves the same as it did before running the file through ffmpeg
So I have been searching around trying to figure out how to fix the timestamps. Presumably they just need to be resequenced so they line up as they should. I looked at the ffmpeg source code where the 'invalid, clipping' message is to see if I could edit it to adjust the timestamps instead of clipping but it is quite a bit over my head.
So that is what brings me here. I have tried both the php script and compiled the latest yaflvfix.c which works fine on linux. The php script gives weird artefacting at the join which other attempts to fix haven't and the same large skip/too short video playback. The yaflvfix program gives seemingly identical results to ffmpeg, but the source code is a lot easier to understand so I think it is the closest I have gotten to fixing this problem.
Now I am trying to work from the yaflvfix source to see if I can edit it to meet my needs, but I was hoping someone could help me as I am completely clueless about all of this. Maybe someone could do it very easily, whereas for me it is very difficult. I know nothing about video streams or editing them at all.
Here is a 12000682 byte sample clip showing my problem. The first 6000000 bytes are from the first video file and contain the unmodified header, the last 6000682 bytes are from the second file which I need to join and of course are taken from the middle of some video/audio data which is identical in both files. This isn't exactly where I need to merge them but is the shortest clip I could make where they overlap. The actual files are much larger.
http://www.mediafire.com/?y2h9o6dml11kaz1
Any assistance people could give with fixing this would be greatly appreciated. If the yaflvfix.c program can be modified to handle this type of file I think that seems most promising right now. As I said this file plays flawlessly in a recent mplayer2 build so there is no video or audio corruption at all, it appears to be entirely a problem with timestamps and how various software deals with the timestamps.
Thank you for reading, and thank you for any help you can give.