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Gop 1 export for YouTube
  • Anyone ever experiment with taking any source, even GOP30 and exporting it with GOP1 to see if it bumps up the YouTube render quality for the end user?
    Interested in reports of user experiences.
  • 7 Replies sorted by
  • I have, and I concluded that it wasn't worth it. Exporting at a higher data rate improves quality more than decreasing the GOP size. Using GOP1 just made the file bigger with no appreciable difference in quality after YT was done recompressing. I would have to lower the data rate just so I could have a file that wouldn't take hours to upload. Not worth it, at least for me. Maybe it'd be more useful for videos with lots of high speed motion.
  • youtube dynamically reencodes videos over time. What you get today may be higher quality in the next few months/years. Its always best to send the highest quality video possible to youtube
  • I understand about exporting the highest quality, I'm speaking here about artificially creating individual frames in a file that aren't there originally, to push youtube into using less compression. Interested in users' experiences as I have had several people recommend this.
    @htinla thanks for the info, interested in other views as well.
  • IME, I always upload the less compressed video if I can.

    Here are some tests for your ref.:
    This is the same video with 4 different settings uploaded to youtube.

    H.264 MP4 format around 30mbps

    (Final File Size on Youtube: 82.7MB)

    H.264 MP4 format around 50mbps

    (Final File Size on Youtube: 93.2MB)

    MOV with Avid Meridien Compressed 2:1 Progressive

    (Final File Size on Youtube: 149.95MB)

    MOV with Avid Meridien Compressed 2:1 Progressive
    This version have more grain added in AE

    (Final File Size on Youtube: 257.2MB)

    All of the file sizes were for "original" quality.
    As you can see, the file size vary significantly.
    But that doesn't means the quality is better, 82.7MB version actually looks better than the 149.95 version (check out that horrible banding) I also think there's something to do with the new player.

    Here is another test with old player:

    H264

    (346.2MB)

    DNxHD mov

    (395.98MB)
  • I guess it is a roll of the dice, because even if it looks better now, they nay re-encode it later. grrrr.
  • @DrDave - "I'm speaking here about artificially creating individual frames in a file that aren't there originally, to push youtube into using less compression."

    Unless you actually increase the frame rate, transcoding a long-GOP video into a GOP-1 format won't create any "artificial" frames. It will reconstruct individual frames out of the motion vectors and residuals contained in the I, P, and B frames in the original file, and then recompress them into a sequence of I-frames. YouTube will then reconstruct the individual frames out of the I-frames in the GOP-1 file, and recompress them into whatever format it deems appropriate.
  • Got it. What about setting the keyframes to "1" on export. I just did a sample yt vid that seemed to look a bit better with keyframes=1. Again, since yt reencodes the video periodically maybe it is a red herring.