video compression / data rate

Discussion in 'General Mac Discussion' started by gernb, May 14, 2003.

  1. gernb macrumors regular

    Jun 6, 2002

    wonder if someone can shed a little light on video compression and data rates.

    i use final cut to edit clips, many of which are placed into power point or media shout for play back on rear project screens at public events.

    i use a canon GL1 to shoot footage so I'm working stictly with miniDV and some Digital Juice clips that are saved with Motion JPEG compression.

    Whenever my final destination is tape or DVD (stuff that will be viewed on TV) I just stick with the DV codec. But more often than not, the clips stay in the computer and are played back through quicktime. In this case, the DV codec is not that great, especially when it comes to motion graphics and text / effects...there are LOTS of artifacts.

    So, i'm looking for suggestions on what are better codecs to use. I've experimented with MPEG-4 and I like it alot. But, I can't seem to find the right balance between data rate and image quality. If I set the data rate too high, I drop frames on playback. if I set it too low, the video breaks down.

    My bigger question is, "Does the amount of data rate my G4 can handle change depending on what codec I'm using?" DV clips play back with a data rate of about 3.6 MB/sec. I find that with MPEG-4 when my data rate is above 1.2MB/sec I start dropping frames.

    Is this just because DV is a more 'efficient' codec?

    Thanks in advance for any tips.
  2. Eniregnat macrumors 68000


    Jan 22, 2003
    In your head.
    I can only help with part of your question. Your video will look better when rendered to DVD because, as I have been told, Apple uses both hard and soft compression for rendering, and the finished product looks better when it in on DVD, v.s. on your HD only.

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