video files question.

Discussion in 'Digital Video' started by axeldtf, May 7, 2012.

  1. axeldtf macrumors 6502

    Joined:
    Mar 3, 2007
    #1
    I have many video file on my mac with various file types (.mov .avi .mp4 etc.). My questions is why do some files seem to make the computer lag? In other words when using quicktime, I have two files..
    file 1) .mov- codec:H.264, AAC, Timecode / 1920 × 816 - 24fps
    file 2) .m4v- codec:H.264, AAC, 1280 x 718 - 60fps

    File one runs a lot smoother on quicktime.. especially when dragging the slider to certain parts. It's larger both in file size and resolution.. File 2 fetches up a lot. I am a novice with stuff like this and just wonder what factors cause issues like this.
     
  2. cgbier macrumors 6502a

    Joined:
    Jun 6, 2011
    #2
    What's the bitrates of those two files?
    How much RAM you have? What CPU/GPU? How fast is your HD?

    These nitbits of info are needed to help you.
     
  3. axeldtf thread starter macrumors 6502

    Joined:
    Mar 3, 2007
    #3
    imac 2 ghz Intel Core Duo - 3GB 667 MHz DDR2 SDRAM [Snow Leopard 10.6.7]
    file one's bitrate is 9,774
    file two's bitrate is 7,779

    How do i check the speed of the cpu?
     
  4. cgbier macrumors 6502a

    Joined:
    Jun 6, 2011
    #4
    Your HD has 5400RPM (IIRC).

    Seems your machine is not really up to task for that heavy lifting.
     
  5. axeldtf thread starter macrumors 6502

    Joined:
    Mar 3, 2007
    #5
    yea i kinda figured.. thanks for getting back to me.. so i should be on the look out for the bit rate?
     
  6. cgbier macrumors 6502a

    Joined:
    Jun 6, 2011
    #6
    It is not only the only the bitrate, but also the compression. For example an AIC with about 100mbps runs smoother than an h.264 with 10mbps, as your machine is not as busy decompressing your footage on the fly.
     
  7. KeithPratt macrumors 6502a

    Joined:
    Mar 6, 2007
    #7
    It's not really the bit rate. Codecs like H.264 have all manner of "tricks" that they can optionally use when encoding. Video files using the more complex ones will require more horsepower to decode. I know of no user-friendly way of finding out how complex a given video's compression is.

    In this case, however, what's being overlooked is that the 720p video is 2.5x the frame rate of the 1080p video.
     
  8. axeldtf thread starter macrumors 6502

    Joined:
    Mar 3, 2007
    #8
    yea and what's odd about that is that file was from eyetv.. which i converted and shrunk the file size with handbrake... before i converted it, it played smooth in the eye tv app.. even though it was larger..
     

Share This Page