Hey Vouk. I got a couple issues and questions I'd like to report.
First, I noticed that there are serious file size differences between encoding with Voukoder vs FFMpeg. For example, I'm doing SVT-AV1 VBR tests now. If I run this simplified FFMPEG command, for example:
ffmpeg -i "TEST.mkv" -c:v libsvtav1 -pix_fmt yuv420p10le -preset 4 -svtav1-params rc=1:tbr=1000 -c:a copy "OUT_FFMPEG.mkv"
versus having a Voukoder preset with VIdeo Input all on AUTO and Video Encoder on with identical settings:
I get completely different outputs with Transcoder. Sometimes much smaller, sometimes much larger, depending on the test file. Are there some defaults that are getting changed that are not seen through Voukoder's GUI? Theoretically, the file sizes should be more or less the same when encoded on the same settings, except maybe for a few kilobytes of metadata, no? In any case, I remembered that MKVToolNix GUI has a very useful option to show the full command line it's using to run MKVmerge. Maybe it would be a good idea to implement something similar to Voukoder for FFMpeg, both for testing and practical uses. Exposing any changed/passed values (if any) without going through the trace log would be great too.
Second, it looks like there is a bug with the Variable Bitrate strategy for LIBSVTAV1. Changing Bitrate and Max Bitrate doesn't change the file size. I tried using 1,000 and 12,000 values and 10,000 and 20,000 values, and the file size stayed the same. Exported through both Premiere Pro and Transcoder.
In order to solve this, I switched back to the "Defined in svtav1-params" strategy. It finally started working, but found a new, very weird problem.
First, I ran these VBR tests on higher presets (5-9) without any issues. But when I switched to Preset 4 or 3, the job couldn't finish. It always got stuck on ~66-84% (depending on the test file) without any errors in the trace log. I then tried different test files and removing every other other svtav1-params except "rc=1:tbr=1000". Absolutely nothing worked. The job wouldn't finish.
I always gave up, thinking it was an SVT-AV1 VBR issue, but then decided to encode with the same settings in FFMPEG. The encode ran fine. Encouraged, I then tried Transcoder and the same scene. It also ran fine (though with a vastly different file size from FFMPEG's). Tried Premiere Pro/Media Encoder again – same issue. So the problem only persists when exporting through Premiere Pro on presets 4 and lower. I tried changing various Premiere settings, increasing tbr (bitrate) massively, and so on – nothing worked. Again, encoding with Presets 5 through 9 worked fine in all cases without any problems. Not sure it's something you can solve, but since it could be a Voukoder-related bug, I'm still reporting it.
Lastly, a heads up: a new major version of FFMPEG (9.0.2) has been out for a while and their major version DLL updates are not backward compatible. I had to get an older 8.1.2 version to grab avcodec-62.dll and few other older DLLs from there. Hope any this is helpful. Thanks.