Maximum supported video length? Avidemux shows incorrect video length.

[gurka]

Hi,

I'm trying to open a video that is 8 hours (08:09:46) long in Avidemux. It loads and plays fine in Media Player Classic but when loaded in Avidemux it tells me that the video is only 3Ã,½ hours long (03:30:09.449). No error or warnings when loading, it just shows incorrect length. I tried searching for a maximum supported video length for Avidemux but didn't find anything. Is this a bug?

File information:

Name: 2016-03-02-2319-01.flv
Size: 3,63 GB (3 908 643 223 bytes)
Video: MPEG4 Video (H264) 1280x720 30fps 4300kbps [V: h264 high L3.1, yuv420p, 1280x720, 4300 kb/s]
Audio: AAC 48000Hz stereo 131kbps [A: aac lc, 48000 Hz, stereo, 131 kb/s]

I'm using the 64-bit version for Windows.


Edit/Update:

I used ffmpeg to cut the video:

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ffmpeg -i 2016-03-02-2319-01.flv -ss 03:00:00.0 -c copy test.flv

It worked fine and a now got a video which I can open in Media Player Classic and is 05:09:47 long, but when I open this video in Avidemux it says that it's only 00:30:09.444 long. So there seems to be "something" at the 03:30:09-mark (00:30:09-mark in test.flv) that makes Avidemux thinks that it's the end of the video.

Both Media Player Classic and ffmpeg shows the correct time, so why would Avidemux think that it's only 03:30.09 long?

ffmpeg output for original file (the 8 hour one):

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Input #0, flv, from '/mnt/3TB-samba/2016-03-02-2319-01.flv':
  Metadata:
    fileSize        : 3908643223
    audiochannels   : 2
    encoder         : Open Broadcaster Software v0.657b
  Duration: 08:09:46.00, start: 0.005000, bitrate: 1064 kb/s
    Stream #0:0: Video: h264 (High), yuv420p(tv, bt709/bt709/iec61966-2-1), 1280x720, 4300 kb/s, 30.30 fps, 30 tbr, 1k tbn, 60 tbc
    Stream #0:1: Audio: aac (LC), 48000 Hz, stereo, fltp, 131 kb/s


Edit 2: I cut a video using ffmpeg that starts AFTER the 03:30:09-mark (at 03:31:00). It loads OK in Avidemux and shows length 04:38:46. 03:31:00 + 04:38:46 = 08:09:46, which is correct. So it seems that the problems is "something" in the video / file at the 03:30:09-mark. Is there ways to turn on debug logs or something similar in Avidemux, so that I can find out what's going on?

[AQUAR]

Does ADM play the whole 8 Hr. video when showing its only 3 Hr. long?

Based on the bit rate of 4300kb/s and file size of 3.63 GB this video should only be around 2 hours long.
4300/8 = 537 KB/s = 32,220 KB/Min
3.63 GB = 3,806,330 KB

Maybe some issues with meta data.
If you provide a sample then the developer might look at it.

[gurka]

No, it stops at the 03:30.09 mark. The bit rate is a bit strange, yes. If you read the output from ffmpeg it shows two bitrates (1064kb/s vs 4300kb/s):

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Duration: 08:09:46.00, start: 0.005000, bitrate: 1064 kb/s

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Stream #0:0: Video: h264 (High), yuv420p(tv, bt709/bt709/iec61966-2-1), 1280x720, 4300 kb/s, 30.30 fps, 30 tbr, 1k tbn, 60 tbc

Could the problem be CBR vs VBR? I think that I deselected CBR when recording this video with Open Broadcast Software (OBS), but maybe it failed to enter this detail in the metadata? I guess that the "bitrate: 1064 kb/s" that ffmpeg outputs is the average bitrate? ADM maybe just assumes that it's a CBR of 4300 kb/s?


I have another video that is 9 hours that ADM also thinks is much shorter. It was recorded using the exact same settings in OBS. It shows correctly in Media Player Classic but ADM shows only 2Ã,½~ hours.


I'll see about uploading the 8 hour file when I get home from work, if someone want to take a look at it.

[mean]

That would help yes

[AQUAR]

@ gurka

Do upload the file, as Mean is the developer and willing to look at the issue.

I was only pointing out the discrepancy to aid your issue.
The two bit rates might be derived differently.
Thinking that the average bit rate is just file-size/time - (the smaller value given by ffmpeg?).