2 Replies Latest reply on Oct 21, 2010 10:23 AM by the_wine_snob

    avi file size compared to m2v file size


      I saved a movie clip in MPEG for computer playback.  The file size was 112MB.  The preset was H.264 1440x1080i 25, no export audio, the codec was MainConcept H.264 Video, TV standard was automatic, frame dimensions were 720 by 480, frame rate was 29.97, field order was automatic, fixed aspect ratio was automatic, level was 4.1, bitrate encoding was VBR, 2 Pass, and Bitrate level was high.  I then saved the file in AVI and the file size was 426MB.  The preset was Microsoft AVI, no export audio, the video codec was Cinepak Codec by Radius, quality was 100, size was 720 by 480, frame rate was 29.97, field type was lowere first and aspect was square pixels.  Why would the file size nearly quadruple and what can I do to get the AVI file size down below 400MB?  Thanks.



        • 1. Re: avi file size compared to m2v file size
          Steve Grisetti Adobe Community Professional

          Well, for one thing, you're going from one format to another -- but, more so, you're going from one codec (compression system) to another.


          The H.264 codec is the one used for creating AVCHD video, although not all H.264 video is AVCHD. It can also be used as a delivery format (that's a format that you display online or play on a computer) -- which seems to be the case here. Your source is apparently from an AVCHD camcorder, although at that file size it must only be about 10 seconds long.


          Though that's hard to say too. Codecs can be highly compressed or lightly compressed, so two files using the same codec and the same file format can be very different in size!


          The Cinepak codec is also a delivery format, though it uses a completely different codec system as well as being for a different file format (AVI). You would neer use a file with a Cinepak codec as source material for editing. It's a highly compressed delivery format. Convert the file to a DV-AVI (an AVI using the DV codec) and it will likely be many times that size.

          • 2. Re: avi file size compared to m2v file size
            the_wine_snob Level 9

            Along with Steve G's comments, there is a big difference in a GOP (Group of Pictures, like the MPEG H.264) and a full I-Frame structure. Plus, the Radius Cinepak CODEC is decades old, and is very ineffective. For background on GOP structure, this ARTICLE might be helpful. For general info on CODEC's, this ARTICLE will give you some background.


            Good luck,