I’m experiencing erratic problems with exported h264/aac MP4 files, where the image freezes part way through a video, while the sound continues. In Windows 10 and iPad video players I can scrub through the video and the sound changes, but the image remains frozen. I’m using Any Video Converter Ultimate (AVC, paid version) to convert videos to h264/aac MP4, 838 x 622 pixels, 30 fps, and then need to trim these frame-exact, which simple video editors like included in AVC, or Clipchamp, or Machete, don’t faclitate. Any ideas where the problem could lie, please?
You have left out some important information. I have questions:
- Since this is a shotcut forum, I assume you are using shotcut as your final step for frame precise editing?
- What version of shotcut?
- What is the original source hardware before using AVC for the conversion. GoPro, smartphone, etc?
- What are the specs from the original source video (resolution and frame rate)
- Can you successfully play the videos back in their original format before going into AVC?
- After the AVC conversion, can you still play the videos back without freezing?
- Assuming the above is true, you are saying the problem starts happening after bringing the converted video into shotcut for frame precise editing? If that’s the case then you might need to do another conversion inside shotcut to “edit friendly” which makes it fixed frame rate and not variable. But that isn’t necessary. See below.
So my final question is this. Why not do the following:
- Simply import the original source video into shotcut
- Set up your video mode to match the 838 x 622 pixels, 30 fps requirement and convert to edit friendly format at this stage (this is important)
- Do your frame precise edits and export as h264/aac MP4 when done.
No extra conversion required and you can work directly in shotcut.
Thanks very much for the detailed response. Answers to the questions:
1 & 2. Yes, I’m using Shotcut version 25.01.25. Indeed, I was going to mention that I’m using the Shotcut edition installed from Microsoft Store, which purports to keep Shotcut updated automatically, and regularly tells me that I’m using the latest version. Not sure, if there is a material difference to the MS Store edition.
3 & 4. The original source is variable frame rate videos from various sources on the internet. The video resolution varies among sources, but is typically about 838x622, and Windows properties reports a frame rate of 30 fps, but this is misleading, as Shotcut reports these files as variable frame rate unsuitable for editing, and suggests converting them first.
5. & 6. Yes the converted videos output by AVC play back perfectly well in a Windows 10 video player. I’m also using Shotcut on Windows 10 Pro, on an Acer E5 with i3 CPU, 2GHz, 8 GB.
7. Correct, this is what Shotcut tells me. The reason for using AVC instead of Shotcut to convert the videos to an edit-friendly format is that AVC takes about 2 mins to convert a video to MP4, which Shotcut takes about 10 mins to convert to ‘edit friendly’, to then be followed by the usual process of trimming and exporting using the ‘edit-friendly’ version. On the other hand, Shotcut also accepts the AVC converted video for trimming without any hitches. I can also scrub through the video on the timeline without any freezes.
Regarding the final question: yes, correct, this would be a way of achieving the desired result. As said, it’s a question of convenience, saving a lot of time by using AVC as an intermediary agent.
As mentioned, what puzzles is me is the erratic manner in which the problem occurs. I could, for example, download three variable frame rate videos from the same same source, and two would work without a hitch using AVC as intermediary, and one would exhibit this image freeze somewhere halfway (indeed, about the mid-point seems to be having this strange attractor) through the Shotcut-edited and exported MP4 video.
In conclusion, it’s not a ‘train smash’, but merely a question of efficiency, and a measure of puzzlement.
OK that makes sense, but there might be another reason the conversion is taking longer in shotcut (keyframe preservation etc etc).
Anyway, what happens when you remove the AVC conversion process on the problematic file?
i.e. import the 2 AVC converted videos that work, then bring in the problematic source video, run an edit friendly conversion on that inside shotcut, do some edits/cuts and export.
Does the problem stay or is it resolved?
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Thanks, an interesting question. I tried that, and had no freezes. Also, several attempts using only the converted files created by Shotcut worked without freezes. I have a hunch that your tip about keyframe preservation hits the problem spot-on. I hadn’t thought of that at first, but in retrospect, keyframe preservation is the one weak spot about which standard video converters won’t care. It doesn’t affect the playability of the converted file, but almost certainly its editability. Thanks a lot!
At least you have a workaround. So now in an attempt to fully solve this you could test one of the problematic files with AVC, changing some of the output settings to see if you can find a preset that doesn’t glitch when Shotcut does the final export.
I’m returning to this post to share my final findings on resolving the problem with video image freezes. Perhaps some future readers might find it useful.
After a lot of frustration and experimentation, the problem turned out to be neither with Shotcut, nor Any Video Converter, nor any specific video file format. The erratic freezes persisted even with video files made ‘edit-friendly’ by Shotcut, and with video files I had shot myself in different formats. Although I never before had any problems with the ‘hardware acceleration’ option in Shotcut’s export dialog, on a whim I decided to turn it off. Freezing problem solved.
It seemed that at some stage something had gone wrong with my hardware configuration (my Acer E5 laptop has an Intel HD Graphic 5500 GPU, with 4.0 GB shared memory; total RAM is 8 GB). Finally, I found that adding a second Acer monitor, permanently connected to the graphics port and permanently switched on, had been the mystery cause. With it connected, hardware acceleration on export causes erratic freezing of the exported video.
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