x265 encoded videos causing random freezes when uploaded to youtube recently

  • I have a feeling this is more likely youtube's fault than Voukoder, but I thought I'd post it here just in case voukoder or x265 is doing something weird causing this. Basically, for the last three 1080p SDR x265 10bit videos I've uploaded to my youtube channel, when I first upload them, I would find random spots in the video where it freezes for a few seconds, and then resumes playback. The first time, reuploading was able to fix the issue. The second time, I contacted support, and they were able to re-process the video, and it worked fine. Today I just uploaded another and had the same issue. The videos play fine on the computer.

    YUV 4:2:0 10bit

    CRF 18

    Everything else default. I used 10bit because I'm doing HDR-to-SDR color grading and I want Premiere to process everything at full bit depth to avoid banding, and since I'm using 10bit, I'm using x265 for that. I believe my most recent 4K HDR video processed correctly, but it's possible it had the issue too and I forgot. I know for sure it was happening on my 1080p SDR videos though. The first time I noticed this was in November, which was my first upload in this format since July. That one worked correctly, as did the 4K HDR uploads I uploaded in September.

    EDIT: I remembered that the time I reuploaded to fix it, I had remuxed to MP4 first. I just reuploaded my MKV hand had the same issue, so I'm going to remux and reupload the MP4 version. Perhaps an issue with the MKV container? Will update after uploading MP4.

    EDIT 2: MP4 appears to be working fine

  • Vouk

    Added the Label Not a bug
  • Vouk

    Removed the Label Adobe Premiere / MediaEncoder
  • Was there anything changed about the MKV implementation in voukoder between July and November that could have caused this? Or is it more likely an issue with something that changed on Youtube's end?

    My HDR uploads are in MKV and worked fine in both September and December, so it's probably not specifically MKV+x265, but it seems to be limited to SDR, or at least, 1080p SDR x265 when combined with MKV.

    • Official Post

    No, but this might have to do with the MKV implementation in FFmpeg. Maybe there were changes in its codebase. But normally a container (esp. MKV) is not that much interested what color format is withing its frames/packets. So i can't really tell.