My screen capture software + codec combination creates video files where the video feed appears to start a bit later than the audio. If I drag one of these video clips to the timeline in Kdenlive and render the project, the resulting video file has no synchronization issues. However, if I try to play the clip in Kdenlive, either through the clip monitor or on the timeline, the audio gets out of sync in a very strange way. Whenever I stop the project and restart playback, the audio jumps forward beyond the current playhead position. If I stop playback and then position the cursor at an earlier point, the audio playback will still resume from a later point. In fact, the audio is never able to go back to an earlier point of playback. If you keep playing, starting, stopping, rewinding, etc., eventually, the duration of the clip's audio will have been played, and any further attempts to play the clip will result in nothing but silence. The previous version of Kdenlive that I was using (don't remember--it was pre KF5) did not have this problem, although I had to trim the beginning of the clip a few seconds once imported onto the timeline if I wanted the audio and video to be in sync. I edited many screencasts in that version of Kdenlive without issues. Reproducible: Always Steps to Reproduce: 1. Download the following video and import it into Kdenlive's project bin: https://dl.dropboxusercontent.com/u/8126161/audio-video-sync-test.avi 2. Play the clip either by A) playing it in the clip monitor, or B) dragging it onto a track and playing the project. 3. Occasionally stop playback and reposition the playhead (both earlier and later) Actual Results: The audio only plays forward, never returning to an earlier point in the audio stream. Expected Results: The audio should be synced with the video. Kdenlive 16.08.2 w/ MLT 6.0.0 OS: KDE Neon 5.8.1 64-bit (Plasma Desktop 5.8.1, KDE Frameworks 5.27.0, Qt 5.7.0)
I have tried with MLT 6.4.1 and Kdenlive 16.12.2 and can't reproduce, could you upgrade both and test?
Created attachment 104472 [details] video showing the bug I can repro this 100% using Kdenlive 16.12.2 with MLT 6.5.0 (appimage). Video attached.
I am affected with this bug too, trying on 16.12.3. my opus music is out of sync when playing both in clip monitor and timeline, a working solution is to remux the file with .mkv Technical details about the .opus file from avprobe: Input #0, matroska,webm, from '...': Metadata: encoder : google Duration: 00:03:02.00, start: 0.007000, bitrate: 129 kb/s Stream #0:0(eng): Audio: opus, 48000 Hz, stereo, fltp (default) Avprobe of the same file remuxed with .mkv: Input #0, matroska,webm, from '...': Metadata: ENCODER : Lavf56.40.101 Duration: 00:03:02.11, start: 0.000000, bitrate: 1764 kb/s Stream #0:0(eng): Audio: flac, 48000 Hz, stereo, s32 (24 bit) (default) Metadata: LANGUAGE : eng ENCODER : Lavc56.60.100 flac DURATION : 00:03:02.113000000 A similar problem appears even when using a .mkv video rendered by kdenlive, it's avprobe: Input #0, matroska,webm, from '...': Metadata: ENCODER : Lavf56.40.101 Duration: 00:00:11.15, start: 0.007000, bitrate: 4660 kb/s Stream #0:0: Video: h264 (High), yuv420p(tv, bt709/unknown/bt709), 1920x1080 [SAR 1:1 DAR 16:9], 25 fps, 25 tbr, 1k tbn, 50 tbc (default) Metadata: DURATION : 00:00:11,127000000 Stream #0:1: Audio: opus, 48000 Hz, stereo, fltp (default) Metadata: DURATION : 00:00:11,148000000 Remuxing, however, does not help in this case.
Ok, sorry, the second avprobe is wrong, that was produced by a Lossless Matroska transcode. This one is from Remux with MKV, still plays correctly: Input #0, matroska,webm, from '...': Metadata: ENCODER : Lavf56.40.101 Duration: 00:03:02.02, start: 0.007000, bitrate: 129 kb/s Stream #0:0(eng): Audio: opus, 48000 Hz, stereo, fltp (default) Metadata: LANGUAGE : eng DURATION : 00:03:02.021000000
I have Kdenlive 16.12.3 on Kubuntu 17.04 with KDE plasma 5.9.4 and Frameworks 5.31. The problem described below also occurred on Kubuntu 16.10 with the same version of Kdenlive. When I load MTS camera files from the same camera, the audio timeline is delayed by about 80ms from the image of the speaker. Using the camera audio with the image there is no problem with this waveform delay. However, I need to load an audio file from the sound desk and create an mp3 audio file which gives better quality than that recorded by the camera. The problem is that when I use the audio timeline waveform to sync with the camera waveform the sound is out of sync with the image and I have to advance it by at least 80ms. This problem occurs randomly on MTS files. I was originally thinking that it was a problem associated with copying files, but because I could reproduce this problem I now think it is with Kdenlive.
Created attachment 105108 [details] Short video segment to show sync problem with video and sound desk audio The audio timeline waveform from the mp3 sound desk file was visually aligned with the camera video timeline.
Samuel, your problem sounds like a different bug than this one. This bug isn't just about out-of-sync audio/video, but rather the case where it is impossible to play earlier bits of audio than whatever audio has been played, even when playing an earlier section of video. If this does not fit the description of what you are experiencing, then you should file your issue as a separate bug report.
Hi Christian. The test file audio-video-sync-test.avi isn’t available anymore. As we have still audio sync issues it would be nice to test it. Could you upload the file again. Can you test with the actual Refactoring Nigtly build: https://binary-factory.kde.org/job/Kdenlive_Nightly_Appimage_Build/lastSuccessfulBuild/artifact/
Created attachment 117188 [details] audio-video sync test Here is the "audio-video-sync-test.avi" referenced in the original bug report.
I am able to repro this bug in the latest Kdenlive nightly (kdenlive-19.03.70-b7d4afd-x86_64.appimage) on KDE neon 18.04 with Plasma 5.14.4.
Task in GitLab: https://invent.kde.org/kde/kdenlive/issues/12 need some testing.
Please see here and test: https://github.com/mltframework/mlt/issues/231#issuecomment-526588347
Adjusting the audio sync does not fix the bug as I reported it. My bug report isn't about a consistent amount of de-synchronization, but rather that when you play, e.g., at timestamp 2:00 in the attached video file and then move the playback cursor to 1:00, the audio continues to play after 2:00 while the video is at 1:00. Eventually, no audio will play back at all on that clip until restarting Kdenlive.
Hi again, are you still experiencing this? I cannot reproduce...
(In reply to farid from comment #14) > Hi again, are you still experiencing this? I cannot reproduce... I just tested with "kdenlive-20.03.70-84910e0-x86_64.appimage" playing the "audio-video-sync-test.avi" file in the clip monitor, and I can reproduce the bug exactly as I described in the original report.
Probably similar to this: BUG431936
Thanks for your detailed report. In fact, MLT cannot work reliably with this file type. I am not exactly sure why, but it cannot be reliably seeked, and Shotcut, the other reference MLT based editor proposes to transcode the file for editing. I will have to implement something simlar
Git commit faf778167d723de182bbbef79450d1f017820dc6 by Jean-Baptiste Mardelle. Committed on 16/04/2021 at 13:02. Pushed by mardelle into branch 'master'. Implement check and transcoding for non seekable files. M +7 -0 data/kdenlivetranscodingrc M +22 -0 src/bin/bin.cpp M +6 -0 src/bin/bin.h M +4 -0 src/bin/projectclip.cpp M +6 -0 src/jobs/loadjob.cpp M +17 -3 src/jobs/transcodeclipjob.cpp M +2 -1 src/jobs/transcodeclipjob.h M +1 -1 src/mainwindow.cpp M +1 -0 src/project/CMakeLists.txt A +67 -0 src/project/transcodeseek.cpp [License: GPL] A +47 -0 src/project/transcodeseek.h [License: GPL] A +101 -0 src/ui/transcodeseekable_ui.ui https://invent.kde.org/multimedia/kdenlive/commit/faf778167d723de182bbbef79450d1f017820dc6