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Jerky Playback

Discussion in 'TiVo Home Media Features & TiVoToGo' started by Soapm, Sep 21, 2012.

  1. Soapm

    Soapm Active Member

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    May 9, 2007
    So close,...
    I just pulled a season of Bilko from the Tivo using kmttg. When I play them using media player classic on my windows machine they play fine but when I play them on my Tivo using pyTivo they appear jerky when motion moves fast.

    How can I determine what needs to be tweaked? I don't know if pytivo is causing this as it sends back to the Tivo or did kmttg have a bad setting when it encoded the shows.
     
  2. Soapm

    Soapm Active Member

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    Can someone please point me to a good video editing forum where one might understand things like telecine, frame rate conversions and other settings that might cause this phenomenon?
     
  3. txporter

    txporter One sec, almost done

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    Sep 17, 2006
    Austin, TX
    Good place to start would be videohelp.com. It is generally a pretty nice forum to wade into video editing. If you get really into it, then you would probably want to move onto doom9.org.

    Do you have something (VideoRedo is what I use) that you can use to cut a small section of video for folks to look at (maybe 10-30s) that shows the problem that you are seeing? That is usually one of the first things that is asked for.

    Nearly all television today is recorded at film rate (23.976 fps) and then pulled down to 29.97fps for broadcast. The Phil Silvers show was broadcast in the 50s though, so I am not really sure how it was shot/broadcast. I would need to look at it. If you can supply a segment of the video, I can take a look at it. Or feel free to use videohelp.com. I have done very little transcoding of older material and there are quite a few folks that sort of specialize in it on various forums.
     
  4. Soapm

    Soapm Active Member

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    So close,...
    Sorry, video redo along with my old editing tools like vdub etc.. all balked at the codec. It really isn't noticeable viewing on a PC but start looking at about the 30 second mark. It's noticeably jerky during movement when viewing via my Tivo.

    here
     
  5. txporter

    txporter One sec, almost done

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    Sep 17, 2006
    Austin, TX
    Will download and take a look at your sample tomorrow (in bed on iPhone now). Is this a sample after conversion or before? Need sample of Tivo file not post transcode.
     
  6. Soapm

    Soapm Active Member

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    So close,...
    This is post transcode. I will have to get the Tivo file tomorrow when I can fiddle with kmttg to keep it from transcoding it.
     
  7. txporter

    txporter One sec, almost done

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    Sep 17, 2006
    Austin, TX
    Ok, great. Need it decrypted but not transcoded.
     
  8. Soapm

    Soapm Active Member

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    So close,...
    Sample 2 Here you go, thanks for taking the time to help...
     
  9. moyekj

    moyekj Well-Known Member

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    Jan 23, 2006
    Mission...
    FYI your Bilko_sample.mp4 seems to play fine with no jerkiness for me on my Premiere but does seem a lot less smooth played on my S3 OLED unit.
    My guess is you have an older series 3 TiVo HD unit right? H.264 decoding improved from series 3 OLED to TiVo HD and then again from TiVo HD to Premiere platform.
     
  10. txporter

    txporter One sec, almost done

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    Sep 17, 2006
    Austin, TX
    This could be.

    Soapm, I looked at your sample and it is just standard film rate material that was telecined to 29.97fps. I noted in your mp4 sample that you can still see the interlacing lines on some of the frames (what profile did you use?). If that is what you were talking about, then that can be fixed with a handbrake encoding profile. I had intended for that to be fixed with the hb_tivo_sd_crf (or hb_tivo_hd_crf) profile. However, I just checked it using kmttg (v0p8r) and it was not actually detelecining. Not sure when that changed. Anyhow, I updated the profile for it to work. Basically, you need to replace "--preset="High Profile" " with "--detelecine --decomb --vfr".

    Note: the --vfr flag can also be set to --cfr to change from variable framerate to constant framerate. I haven't looked into what exactly handbrake does for constant framerate, but I would guess that it would repair the telecined frames but not remove the duplicates (every 5th frame would be a duplicate frame resulting in a bit of judder). You can play around with it to see if it matters for you. If you do have an older S3, then it might like the 29.97fps more than the 23.976-24 fps you will get from vfr.

    moyekj, since you are here in the thread, would you mind updating those encoding profiles for your next release? :)

    hb_tivo_sd_crf:
    Code:
    # Description (single line, keep short)
    <description>
    Handbrake tivo sd: mp4 container, Constant Quality (CRF=19) h.264 video, ac3 audio
    
    # Encode command or script (single line)
    # Known keywords: FFMPEG, MENCODER, HANDBRAKE, PERL, INPUT, OUTPUT, PWD, CPU_CORES, SRTFILE
    <command>
    HANDBRAKE -i INPUT --detelecine --decomb --vfr --large-file -e x264 -f mp4 -O -q 19.0 -a 1 -E ac3 -x keyint=48:min-keyint=4 
    
    --denoise="weak" -v -o OUTPUT
     
    # Encoded output file extension
    <extension>
    mp4
    hb_tivo_hd_crf:
    Code:
    # Description (single line, keep short)
    <description>
    Handbrake tivo hd: mp4 container, Constant Quality (CRF=21) h.264 video, ac3 audio
    
    # Encode command or script (single line)
    # Known keywords: FFMPEG, MENCODER, HANDBRAKE, PERL, INPUT, OUTPUT, PWD, CPU_CORES, SRTFILE
    <command>
    HANDBRAKE -i INPUT --cpu CPU_CORES --detelecine --decomb --vfr --large-file -e x264 -f mp4 -O -q 21.0 -a 1 -E ac3 -x keyint=48:min-keyint=4 --denoise="weak" -v -o OUTPUT
     
    # Encoded output file extension
    <extension>
    mp4
     
  11. Soapm

    Soapm Active Member

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    Yes, I have a tivo HD but I noticed xvid plays fairly clear for me but I still have a CRT...

    i will try the new profile when I get home. I believe I use Tivo SD in kmttg but that was done using the normal profile directly in handbrake... I have all CRT's so never saw the need for going with HD profiles.
     
  12. moyekj

    moyekj Well-Known Member

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    Mission...
    xvid will be transcoded to mpeg2 on the fly by pyTivo so what your TiVo is getting is mpeg2 which may explain why that looks OK on your TiVo HD. TiVo HD is good at mpeg2 decoding but picky about H.264 decoding. You can actually force pyTivo to transcode H.264 to mpeg2 as well if you wish by putting certain directives in a metadata file.
     
  13. txporter

    txporter One sec, almost done

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    Austin, TX
    Agree with what moyekj said about xvid. xvid will always be transcoded to MPEG2 when either pulled or pushed from pytivo.

    For the mp4/H.264 files, are you pushing them from pytivo to your TivoHD or pulling?

    Also, the HD comment is really based on the incoming resolution of the file, not what it is displayed at on your TV. Higher resolution files can run with a higher quality factor and still give good output video.
     
  14. Soapm

    Soapm Active Member

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    Sorry, I had to work late last night and tonight.

    What constitutes resolution? Is it the 720x480 or the video bitrate? Or maybe a combination of both?
     
  15. jcthorne

    jcthorne Active Member

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    Houston
    720x480 is SD not HD.

    Broadcast HD is either 1280x720 p60 or 1960x1080 i30.
     
  16. moyekj

    moyekj Well-Known Member

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    Mission...
    @jcthorne, thanks, I updated hb_tivo_sd_crf and hb_tivo_hd_crf kmttg profiles per your post for next release.
     
  17. txporter

    txporter One sec, almost done

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    Austin, TX
    @Soapm: As jcthorne indicated, the resolution is the frame size (i.e. 720x480).

    SD = standard definition is what we were used to with NTSC broadcasts that ended in 2009 in the US. The most common resolutions for US SD to be broadcast in was 640x480 and 720x480. DVD is also SD resolution. I believe all US NTSC broadcasts as well as US DVD are run at 29.97fps.

    HD = high definition is what we see now with ATSC broadcasts. Most common resolutions for HD are 1920x1080 and 1280x720. 720p transmissions are sent as 59.94 progressive frames. 1080i transmissions are sent as 59.94 interlaced fields.

    @moyekj: Thanks for updating the profiles.
     
  18. Soapm

    Soapm Active Member

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    So close,...
    I used the updated Tivo_SD profile today and it appears a lot better. There is still something about fast movement that appears as jerkiness but it's definitely a lot better and watchable now so I appreciate it very much.

    I also noticed the shows look and play fine on my premier.
     
  19. unitron

    unitron Active Member

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    Apr 28, 2006
    semi-coastal NC
    Bilko, being B&W, would likely have been broadcast at a 60Hz vertical sweep, resulting in 60 fields/30 frames.

    It wasn't until "Never Twice the Same Color" that they dropped it to 59.whatever for some reason connected to the 3.58Mhz color sub-carrier.

    I thought actual, like they used in Hollywood, film was a straight 24 frames per second, though.

    And I guess they ran the film through a flying spot scanner for the original broadcasts. CBS, if I remember correctly.

    They should have had Hartman play Bilko in the movie instead of Martin.

    He could have done an excellent Silvers.
     
  20. txporter

    txporter One sec, almost done

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    Sep 17, 2006
    Austin, TX
    I suspected something like that might be the case. But the sample that Soapm sent me looked like straight 3:2 telecine material.

    @Soapm- Try updating the profile again and change the --vfr flag to --cfr instead. It will output 29.97fps video rather than 23.976fps. I found that TivoHDs would get a sort of shimmer effect on video with <25 fps. Running at 29.97fps might fix the problem for you.
     

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