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mp4 transcoding appears to be eliminated

Discussion in 'TiVo Home Media Features & TiVoToGo' started by larry99, Feb 18, 2009.

  1. txporter

    txporter One sec, almost done

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    Sep 17, 2006
    Austin, TX
    Ok, I follow that. The mp4s that I have pushed so far have been 23.976 fps progressive and have played fine.

    One question though, all of the 10min clips have had green blocky (stuff?) in the first few seconds of the video. I saw a post about this in the streambaby thread from westside_guy. I didn't see a solution for it. Does anyone know what is causing this or how to fix?

    Jason
     
  2. Yoav

    Yoav New Member

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    Jan 12, 2007
    oh iTiVo!! (sorry my bad I should have figured it out).

    Do you know which 'format' you used as the basis? I'm looking at all the movies I created with iTiVo, and all the ones I've checked so far are mp4's with a framerate of 29.97

    -- yoav
     
  3. NA9D

    NA9D New Member

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    May 26, 2008
    Algonquin, IL
    Oh, it's the iPod/iPhone Super-Res setting. Perhaps there's something in that?
     
  4. Yoav

    Yoav New Member

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    Jan 12, 2007
    Just tried using iphone super res on my computer:

    Code:
    Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/Users/yoav/Desktop/tivo/The Daily Show With Jon Stewart - Tom Selleck.mp4':
      Duration: 00:00:29.01, start: 0.000000, bitrate: 1457 kb/s
        Stream #0.0(und): Video: h264, yuv420p, 640x480, 29.97 tb(r)
        Stream #0.1(und): Audio: aac, 48000 Hz, stereo, s16
    At least one output file must be specified
    
    So that's not the problem... (I also tried adding a -delay 0.25 to see if that changed anything.. nothing changed).
     
  5. txporter

    txporter One sec, almost done

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    Sep 17, 2006
    Austin, TX
    The seeking (FF/RW) within a mp4 is choppier or more discrete than the MPEG2 tivo recordings. Is this due to the decoding requirements of mp4 on the tivo, or is this something I can affect with min/max GOP (or something else) when encoding?

    Jason
     
  6. euckersw

    euckersw New Member

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    Jan 30, 2004
    Just in case anyone was going to try this, mkv2vob does not remux mkv files to mp4 files (in fact, it really only renames the resulting mpg to mp4). I've looked around for other good solutions for remuxing a mkv to mp4, but have yet to find one. Please let me know if you anybody else has any success...
     
  7. moyekj

    moyekj Well-Known Member

    11,140
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    Jan 23, 2006
    Mission...
    There is the ffmpeg way, though it may lead to audio/video sync problems. Something like:
    ffmpeg -i "file.mkv" -acodec copy -vcodec copy -copyts -f mp4 "file.mp4"

    i.e. copy audio & video & timestamps and mux into mp4 container.
     
  8. NA9D

    NA9D New Member

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    May 26, 2008
    Algonquin, IL
    I'll check another encode with your software. Maybe this one was done with Visual Hub or something. I've used that in the past and thought this one had been done by iTivo but maybe not...
     
  9. Rdian06

    Rdian06 New Member

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    Apr 12, 2008
    Technically that is the ffmpeg way, but -acodec copy into -f mp4 is horribly broken right now. The code fails to set the audio framesize (and apparently the bits per sample as well) for "copy" and so it bombs out immediately with an error.

    And when you start with ac3 5.1 channels in the mkv and do:

    ffmpeg -i "file.mkv" -ab 448k -ar 48000 -acodec ac3 -vcodec copy -copyts -f mp4 "file.mp4"

    ffmpeg reports that it is transcoding from ac3 5.1 to ac3 5.1 in the console output, but ffmpeg -i on the resulting mp4 shows ac3 stereo. I think it's hard coding the header info somewhere :(

    All in all, ffmpeg's mp4 muxing isn't very reliable right now. I tested all this with an ffmpeg SVN snapshot from last night.
     
  10. NA9D

    NA9D New Member

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    May 26, 2008
    Algonquin, IL
    Yoav

    That encode was done with iTivo, but I'm not sure how. All my other iTivo encodes show up fine. So not sure what happened with that one...
     
  11. Yoav

    Yoav New Member

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    Jan 12, 2007
    If I understand you right, iTiVo made the 60fps video for sure, but that's the only one that seems to be 60.. all the others were 29.97?

    I guess we need to figure out if there was somehting unique/special about the source movie that iTiVo encoded (the flags to mencoder do not specify a new framerate, so I'd guess that the source was 60fps... except broadcast TV doesn't do 60fps -- so I'm at a loss for now..)
     
  12. wmcbrine

    wmcbrine Ziphead

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    59.94 fps is standard for 720p. So yeah, broadcast TV does it. ;)
     
  13. Yoav

    Yoav New Member

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    Jan 12, 2007
    Whoa I thought 720p was 30fps (progressive, but 30fps anyways).

    Ok, well we now know how he got the file then :). He must have downloaded from a channel broadcasting in 720p. I'm gonna assume that the 60 fps is not a bug then...
     
  14. jcthorne

    jcthorne Active Member

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    Jan 28, 2002
    Houston

    I got megui to work. mp4 muxer under tools menu. Unfortunatly the output shows the ac3 audio as stereo not 5.1 like the original and MPC will not play the file as is. It did transfer to the tivo. But has aspect ratio and folderization problems.
     
  15. jcthorne

    jcthorne Active Member

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    Jan 28, 2002
    Houston
    I also cannot say for sure but if your problem that you cannot talk about is anything similar to my problem that I could not talk about,

    changing mind.tivo.com to stagingmind.tivo.com in the file mind.py may fix you up for now. Or not.
     
  16. NA9D

    NA9D New Member

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    May 26, 2008
    Algonquin, IL
    I was going to make that comment that wmcbrine made that 720p is at 60 fps, but he beat me to it. Most progressive formats (480p, 720p, 1080p) are at 60fps. The only exception really are some movies encoded at the original 24 fps (Vudu does this with their 1080p movies for example). But no one uses 24 fps in broadcast. Keep in mind that the 30 fps for 480i and 1080i is really two interlaced frames so it still really is 60 fps...

    Anyhow, it must have been recorded from an HD channel but I'm not sure why I would have recorded a cartoon from an HD source! And what's odd is that none of my other HD content is showing up this way...Most channels use 1080i and not 720p. Guess I'll have to record a definite 720p show and see. I think ABC uses 720p and PBS. I forget but it's not hard to find out.
     
  17. wmcbrine

    wmcbrine Ziphead

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    Aug 2, 2003
    ABC and Fox are 720p. Also ESPN, National Geographic and DirecTV 101. PBS is 1080i at the network level, but some affiliates moved to 720p so they could squeeze more subchannels in. There's also a 1080i ABC affiliate out there.
     
  18. NA9D

    NA9D New Member

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    May 26, 2008
    Algonquin, IL
    I'm downloading an episode of Sarah Connor Chronicles now using iTivo. We'll see what we get! :)
     
  19. txporter

    txporter One sec, almost done

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    Sep 17, 2006
    Austin, TX
    I attempted to push a mp4 last night with AC3 audio and it forced a transcode. Not sure what the issue is there, but since I only listen in stereo, it's no biggie to convert the audio to 2ch AAC.

    I am also fairly certain that pushing mp4 to my Tivos (well, I have only pushed to one of them) is somehow killing its ability to connect to the tivo servers for the service connection (even when not pushing video). Has anyone else seen this? I will check more into this over the weekend.

    I am still seeing green blocky artifacts in the first ~5s of every video uploaded, XVID4PSP created, Handbrake w/ Web optimized and Handbrake w/o Web optimized. Am I the only one seeing this?

    Jason
     
  20. NA9D

    NA9D New Member

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    May 26, 2008
    Algonquin, IL
    I see this quite often when streaming, etc. On my Roku Photobridge it would happen fairly frequently when doing FF/RW through files.

    I think it's just that all the different patterns on the file get out of sync initially (not sure how to describe it better than that) and then it gets figured out and assembled correctly...
     

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