Cutting HD-Videos makes video much slower than audio

[maximalz]

Hi all,

I'm using avidemux 2.5.3 on Ubuntu Precise. When I try to clip away start and end of HD videos (e.g. from onlinetvrecorder), the result's video is much slower (approx. 1/4 the speed) than the audio track (which has normal speed).

Am I doing something wrong or is cutting HD not possible under Linux? My friend does the same under Windows and has no problems.

Kind regards

Max

[Jan Gruuthuse]

Update to 2.6 if on Ubuntu 12.04.1 LTS (Precise Pangolin).
32-bit update: nightly builds precise 32-bit
64-bit update: avidemux Cli/QT/GTK 2.6 64-bit deb download ubuntu 12.04
how to install 32/64 bit) see 64-bit posting.
Best you upload a sample 20 MB , developers may have a look at it. Could be an issue with indexing?

[maximalz]

I tried to update, ignoring the "this package is of bad quality" warning. I succeded with core, core-plugins and gtk until it comes to installing the gtk-plugins, which fails. I need to say, that I'm running on amd64 (A4) and the binaries are compiled in Intel core i5.

Nevertheless the gtk application starts, but there is no possibillity to scroll inside the movie, I can shift the slider but without effect. So I can not decide whether the problem is fixed with 2.6.

Any other ideas?

[Jan Gruuthuse]

Don't use GTK use QT 4.
If you use provided download from my thread, and on ubuntu uses softwarecenter. Search for avidemux3 and des-install
- cli plugin, gtk plugin, qt4 plugin, common plugin
- cli, gtk, qt4, core
install in this order:
- core, common plugin, QT4, qt4 plugin, cli and no other plugins.

If you compile yourself: check cmake version:

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cmake --version
If cmake < 2.8.8 please update and build cmake on your system:

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cd ~/cmake
./bootstrap
make
sudo make install
replace when needed: "cd ~/cmake" is your current user home folder "cmake"
cmake <- click

[maximalz]

So thanks for this info. I tried to use your debs, they installed and the application started. I could load a avi and it builds a time map, but I could not seek by either moving the slider or entering times in the play-time box. Using the "wheel" at bottom right gives me an error "Cannot go to previous keyframe".
I also compiled with cmake 2.8.9 from source, uninstalled all avidemux3 before installing self-compiled debs. Same effects.

[maximalz]

I would very like to upload a sample, but when I take the first say 20MB (e.g. with dd) avidemux not even opens the file.
I'd also like to say, that I'm very fond of unix but have no plan of video cutting etc. and am really happy getting some help here. Thanks.

[styrol]

I could load a avi and it builds a time map, but I could not seek by either moving the slider or entering times in the play-time box. Using the "wheel" at bottom right gives me an error "Cannot go to previous keyframe".

There is missing timing information in the AVI (h.264/mp3) files produced by OTR, cf. also this topic.

but have no plan of video cutting etc. and am really happy getting some help here.

dd is the way to go as explained in the wiki: http://www.avidemux.org/admWiki/doku.php?id=tutorial:cut_ts_sample

As a workaround you can save your source file as mkv (using copy mode), then cut a sample and resave it as AVI; all done with Avidemux

The better way is to cut your file using winff (ffmpeg fronted for both Windows and Linux):
(1) At first create a profile:
     profile name: avicopy
     profile description: AVI (Copy)
     commandline: -vcodec copy -acodec copy
     file extension:avi
     category: AVI
(2) Load your source file (your OTR file)
(3) Select AVI under "Convert" and AVI (Copy) under "Profile"
(4) Under "Options" / Time: specify video length: from 0:00:00 to 0:01:00 (= 1 minute)
(5) Press "Convert" (actually a simple remuxing, no re-encoding)

[Jan Gruuthuse]

I found 2 avi samples from the OnlineTvRecorder:
Standard Definition video: looks like only every 8 seconds there is a keyframe.
High Definition video: looks like no keyframes are found/recognized.
Each download max. 29 MB: SDvideo HDvideo

[styrol]

High Definition video: looks like no keyframes are found/recognized.

HQ and HD AVI files  (MPEG-4 AVC / MP3):
Well, there are keyframes in my own HQ samples and in your HD sample at least indicated by other programs, but Avidemux misses timing information:

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There is more than 5% unavailable PTS, wont even try (98961/98962)...
  [ADM_setH264MissingPts]  End of game, we have 98961 missing PTS
Opening such file there is the notification "Building time map" but no "Unpacking bitstream".

SD AVI files (MPEG-4 ASP / MP3):
No problem here for Avidemux to jump from one keyframe to another. Opening such file there is the notification "Unpacking bitstream" after "Building time map".

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we have 91448 valid DTS and 1 valid PTS
  [ADM_computeMP124MissingPtsDts]  We also have 0 bframes
  [ADM_computeMP124MissingPtsDts]  We have 0 fields and 91448 frames
  [ADM_computeMP124MissingPtsDts]  No bframe, set pts=dts

HQ MP4 files (MPEG-4 AVC / AAC):
No problem here for Avidemux to jump from one keyframe to another.

The problem seems to be related to h.264 in AVI container produced by OnlineTVRecorder. The SD file contains simple MPEG-4 Part 2 encoded video.

[maximalz]

So is there a possibility to create these keyframes, i.e. can I make the OTR files usable for avidemux or can I cut them with a different program?

[styrol]

So is there a possibility to create these keyframes, i.e. can I make the OTR files usable for avidemux?

Re-encoding creates new keyframes. Or as I suggested in another topic (linked above) you can save your video as MKV (Copy/Copy) in Avidemux and try to edit them.

can I cut them with a different program?

On OS X and Windows yes. I'm not familiar with Linux, but this may help:
http://wiki.onlinetvrecorder.com/index.php/Cutlist-Austausch/Linux