Avidemux Forum

I'm very happy with Avidemux, but recently I see lot of freezes when processing interlaced content.

My Avidemux (2.8.1) is freezing when applying Merge Fields filter from Interlacing section. What I'm trying to accomplish is to convert from 50 FPS 1920x540 to 25 FPS 1920x1080.

The freeze occurs at end of first pass. Empty dialog box is thrown and Avidemux freezes.

Have found similar topic here but it seems as abandoned or resolved (depending what posts you look at).

Below is information about video file, py script and log file from Avidemux ending with:

[ADM_Composer::nextPictureInternal] 20:39:12-839 Next image PTS in ref is out of range: got 3951040000 us, wanted < 3951025378 us, discarding the image
[ADM_Composer::searchNextKeyFrameInRef] 20:39:12-839 Found nextkeyframe 3951780 1:5:51 at frame 197308
[ADM_Composer::nextPicture] 20:39:12-839 Cannot get next picture. Last segment
[ADM_videoFilterBridge::getNextFrameAs] 20:39:12-839 [Bridge] Base did not get an image
Saving crash file to C:\Users\Ice\AppData\Roaming\avidemux\crash.py
   ...   <Skipped some lines>   ...
Crash Dump for Assert failed :src->_height==_height at line 29, file F:\jenkins\workspace\VS2019_no_import\avidemux_core\ADM_coreImage\src\ADM_imageOperation.cpp

Have I done something wrong or is this bug?

Crash log of Avidemux: You cannot view this attachment.
Media info of file being processed: You cannot view this attachment.
Py script file of Avidemux (Filters applied in order "Merge Fields" - "DelogoHQ" - "Crop"): You cannot view this attachment. (zipped due to py not allowed to upload)

Edit: There are cuts done to the file, but cuts are done only on keyframes (with up and down arrows).

OK, thanks for the answers. I tested it again and it seems in copy mode it will just silently cut the output file to keyframes instead of giving a warning. So it kind of works like the record feature in VLC, but definitely gives more solid results than that, and is much faster of course.

However, I still don't understand why the resulting frame rate is off by about 0.002 frames or so. When doing +10 seconds seeking in VLC, comparing with the source, it indeed doesn't always land on the same frame. This suggest to me that even when cutting by keyframes, there might be a duplicate or missing frame somewhere in the video.

To reencode you must choose an encoder option in the Video Output drop down list. Copy is selected by default. Once an encoder option is selected the Configure button becomes active and you can apply quality settings.

Because most (not all) I-frame referencing is done in a backwards direction, you must always start on an I frame, but you can often end on an intermediate frame. It is therefore possible to get very accurate results without reencoding, but there is no guarantee.

Version 2.8.1 is now very old. The latest nightlies can be found below:

https://www.avidemux.org/nightly/win64/

Lossless cutting must start on I-frame, this is due to physical/mathematical/information-theoretical principles. The end frame rule depends on the frame structure of the source material.

Copy mode or reencode is fully controlled by the user. If Copy mode selected, there is no reencode happens.
The headphone downmix option only affect the playback in Avidemux.

Hello,

when looking up the subject of lossless cutting in avidemux, I found a lot of older threads that all suggest the same: in avidemux, lossless cutting is possible, but only if the start and end frames are I-frames (keyframes). If at least one of the two is not an I-frame, a warning is supposed to appear during exporting, and when exporting, it will reencode the resulting video. Reencoding is supposed to be quality controllable via a slider.

However, this behavior does not match what I'm seeing in the latest version. There is no encoding quality option, for one. I'm also able to cut on any frame I want, and it will export the video all the same, witout any warnings. Comparing with the source, I can't spot any differences, but VLC will always show a framerate that is off by a fraction, compared to the source.

Can anybody clarify if lossless cutting is still possible in 2.8.1, or is it always reencoding the video now, presumably with highest quality? And another minor question - I noticed that a headphone downmix option is enabled by default. I'm assuming this is just for playback and doesn't need to be changed when both audio and video are shown as "copy"?

New version: https://github.com/martin-holy/Avidemux_scripts
# 2024.10.02
# - bug fix: decode profile not set because it was not copied to AppData\Roaming\avidemux\pluginSettings\x264\1\

for so long i thought it was working 🤦🤣

I'll give it a try.

I am using Ubuntu 24.04, customized for my own purpose.

edit: Now builds successful again

Quote from: eumagga0x2a on February 24, 2021, 06:58:21 AMYou need to specify the needed rotation in the configuration of the MP4 muxer.

This setting only affects video rotation when you save it without encoding, is there way to turn it 90 degree in preview on main window?

Even if enable re-encoding and use rotation filter still in main window video shows sideways.

Thanks, go->last frame worked.

"Edit" --> "Reset Markers" (press "R" with alternative keyboard shortcuts enabled). This selects the entire video, removing the blue selection rectangle, which is the default state.

For an extreme rare case of need to place the B marker to the last picture rather than to the end of video (which is beyond the last picture), navigate to the last frame ("Go" --> "Last Frame", press "E" with alternative keyboard shortcuts enabled), then press "O" (capital "o") with alternative keyboard shortcuts enabled.

In doubt, always use the latest available nightly build for your platform.