Need help in getting HD 264 files to play nice

Discussion in 'Digital Video' started by treehorn, Apr 22, 2011.

  1. treehorn macrumors 6502


    Aug 21, 2007
    I do a lot of editing of promo spots that incorporate Brolls from shows with interview footage from opening nights, etc. The Brolls come to me on everything from standard DVD, BetaSP, raw DV/DVCPRO Quicktime and HD files in...a variety of formats. The interviews are either DV/DVCPRO or HDV depending on who shot them.

    Lately I've been having problems with getting them to play nice with each other - specifically, clips from one company are getting very pixilated/blocky when I get the final product compressed down for web (the settings are close to the preset for Ipod Video 640X480 - unfortunately the preset is on my work computer and not here at home).

    The odd thing is that those clips sometimes work beautifully, sometimes look unusably horrible and there is no rhyme or reason (and as I wasn't the one that initially made them, I have no idea if they did something different on their end in compressing them). I've tried converting the clips into whatever format I'm going to be editing in ahead of time to match the interviews, but it makes no difference - it will look great until compressed down to the preset (which if memory serves is 1000kbps instead of the 1500kbps - I'm sure this doesn't help but as everything else looks fine at that level...)

    The Settings on the clips that are giving me problems are:

    Data rate - Between 8 and 12MB/Sec
    Square pixel
    Upper field dominance

    I've tried simply dragging them into the timeline and having FCP render them (usually into a DV/DVCPRO 720X480 Lower Field sequence. Sometimes into an HDV sequence). I've tried using Compressor to convert them into DV NTSC ahead of time to make them match the other footage. Neither shows any difference.

    Since it doesn't happen with every instance of using clips from this company in this format, I'm not sure where or what the problem is occurring. and since it sometimes results in such a glaring difference in the same sequence (imagine the most pristine HD followed by the worst Youtube clip)...

    Any help/advice would be greatly appreciated
  2. Erendiox macrumors 6502a


    Oct 15, 2004
    Brooklyn NY
    So H.264 is a very compressed format. That sets off a flag right there. Ideally you wouldn't be provided footage in such a lossy format.

    Taking the H.264 footage and converting it to DV NTSC is essentially compressing it again (albeit a lesser compression), but it is still increasing the generation count. Instead, I would try throwing it into compressor and transcoding to apple prores 422. That should hopefully alleviate any loss of quality.
  3. CaptainChunk macrumors 68020


    Apr 16, 2008
    Phoenix, AZ

    When working with multiple formats, it's advisable to conform everything to one codec. If I were you, I'd transcode everything to the lowest denominator (in your case, standard-def at 4:3 or 16:9 aspect, depending on your delivery needs) and use a good intermediate codec like ProRes 422.

    Doing that would eliminate the need to render the timeline constantly and deal with frame scaling from multiple formats of video sitting in the same sequence.
  4. treehorn thread starter macrumors 6502


    Aug 21, 2007
    But sadly we don't live in an ideal world :) And this is footage given out for television usage, believe it or not...(do CBS Sunday Morning and the Today Show really like getting footage in compressed h.264?)

    I'll try prores 422. My thought was that as the the other footage is DVPro NTSC converting it to DV NTSC would be transcoding to a closely matching format. But it didn't seem to help any...
  5. KeithPratt macrumors 6502a

    Mar 6, 2007
    NTSC DV is 4:1:1, which is terrible on its own, and doubley terrible if the originating H.264 clips were SD, as you'd be going from 4:2:0 to 4:1:1, so effectively ending up with 4:1:0.

    Is this what you're seeing? You need to be exact about when exactly it starts looking like garbage.

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