5 Replies Latest reply on Nov 7, 2010 5:07 AM by Jeff Bellune

    Glitchy Artifacts and Blocks in 1080p H.264 Encodings - HELP

    flowingfire

      Hi.  I'm curious if anyone else has the same problem I'm having with glitches and artifacts appearing then disappearing in high-bitrate HD video.

       

      Any ideas? I read about other people with similar issues, but it's so hard to pin down.  Is this a hardware issue?  What actions can I take to prevent this kind of encoding problem?  It's not a playback problem, and can be reproduced consistently.  The original videos are perfect-- no glitch.

       

      This happens when I encode H.264 videos in Premiere Pro or Adobe Media Encoder.  The videos will turn out perfect except for about a second or two in any given video that has noisy artifacts disrupting small areas within the video.  Everything else about the videos are the high quality I would expect.  This happens whether or not I choose VBR 1 pass or VBR 2 pass.

       

      The settings I generally use are:

       

      FORMAT: H.264

      PRESET: 1080p 29.97 High Quality

       

      Custom Changes: Occasionally I change from VBR 1 pass to VBR 2 pass.

      Maximum Render Quality: Checked

       

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      Also, I noticed that when I do VBR 2 pass, and I also use Media Encoder, the encodings encounter unknown errors and fail nearly 100% of the time.  Not the case within Premiere.  Strange.

       

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      I performed the PPBM5 benchmarks, and the result is: 694 secs Total Benchmark Time.  (It's not great, but I still can't explain the artifacts.)

       

      Premiere Version: Premiere Pro CS5 5.0.2

      OS: Windows 7 Ultimate

      Processor: AMD Phenom II X4 965 BE

      Primary Drive: 7,200 RPM High Performance drive

      RAM: 4 GB  (I know, I know, skimpy.)  .... Would more RAM solve this?

      Video Card: NVIDIA Geforce GTX 460

        • 1. Re: Glitchy Artifacts and Blocks in 1080p H.264 Encodings - HELP
          Jeff Bellune Adobe Community Professional

          What are your bit rate settings?

           

          The MainConcept H.264 encoder has had issues in the past with insufficient bit allocation at I-frames during VBR encoding.  I first saw it when using it to encode H.264 video for mobile devices.  Sorenson Squeeze  solved it by opening up and modifying some more of the encoder's parameters.  To do similar in Pr/AME, I would leave some headroom between the Target bit rate and the Max bit rate.  FWIW, I use Squeeze to encode all of my H.264 stuff, so I don't have any recent AME results to evaluate.

           

          -Jeff

          • 2. Re: Glitchy Artifacts and Blocks in 1080p H.264 Encodings - HELP
            flowingfire Level 1

            Thanks for the response, Jeff!  Question: would switching over to CBR work better?

             

            Generally, my bit rate settings are at the pre-sets.  For example, 1080p at 32 Mbps target and 40 maximum.  Or, when encoding at 720p, 6 Mbps target and 10 maximum.  Right now I'm testing out a 720p encoding setting with 6 target and 20 max.  I'll let you know how that goes.

             

            That said, I tried the 1080p already extending the maximum to 50 Mbps.  The encoding failed altogether and crashed AME.  ...  More RAM needed perhaps?  Maybe I'll try your "Squeeze" program instead of Adobe. lol..

             

             

             

            Oh, I should probably add that the glitching happens in 720p encodings as well.  Interestingly, I'm noticing that the encoding I'm having the most trouble with are videos including excessive camera flashing. (Though the glitching seems to have nothing to do with the flashing itself, as it's at different spots...)  Could this have something to do with it?  Nonetheless, the glitches show up everywhere... even in completely serene, still, and calm nature sequences.

            • 3. Re: Glitchy Artifacts and Blocks in 1080p H.264 Encodings - HELP
              flowingfire Level 1

              I just wanted to update you on the 720p H.264 encoding with the added bitrate leeway.  I managed to encode a video without a glitch that I've tried to encode about 6 times before.  Perhaps there's something to what you were saying!  Yayyyyyyy!  (Maximum render quality, 2 VBR pass, etc.)  Oh excitement and glee! I'm hoping that that wasn't just an isolated success and that at least the problem is solved at 720p.  We'll see!

               

              Unfortunately, trying the same thing at 1080p did cause unknown errors and crashes.  Blah!!!!!  That said, AME still constantly crashes trying to do 2-pass VBR while Premiere Pro does not. (???????????????? HUH???????)

               

              Thoughts?

              • 4. Re: Glitchy Artifacts and Blocks in 1080p H.264 Encodings - HELP
                Jeff Bellune Adobe Community Professional

                What is the final destination for your 1080p video?  Blu-ray?  If so, then try an H.264 Blu-ray preset instead of just H.264.

                 

                Please post your exact AME settings that caused a crash, as well as the exact sequence settings from the source sequence.  Finally, please post the source video properties, including the camera model that was used.

                 

                Thanks,

                -Jeff

                1 person found this helpful
                • 5. Re: Glitchy Artifacts and Blocks in 1080p H.264 Encodings - HELP
                  Jeff Bellune Adobe Community Professional

                  For some background on the MainConcept H.264 encoding problem, please visit the following web page, and scroll down to the H.264 section:

                   

                  http://www.streaminglearningcenter.com/articles/sorenson-squeeze-5.html

                   

                  As I said, Squeeze fixed this in an update to version 5, and it remains fixed through version 6.5.

                   

                  -Jeff

                  1 person found this helpful