Converting avi files

Question

Hi, I have been given the task of creating a film in imovie using clips of avi files shot on a creative vado (non HD).
I have quicktime pro version 7.6.4 (518.35). When I attempt to open the avi files to convert to work in imovie I get a message saying my version of quicktime does not contain the necessary components. Please can someone help and also let me know what is the best export/conversion settings??
Regards
Steve

Answer 1

Statement does mean files from QT to DV have audio but but following same route in streamclip the audio disappears. Streamclip app downloaded fresh from their site and tried current and new beta version with same poor results... Checked movie properties on AVI file and contains video xvid 1.0 and audio microsoft ADPCM file. When converted to DV in QT video changes to DV - PAL and audio to DV. When using stream clip video changes to DV - PAL and audio to DV but sound doesn't work??????
Very strange. Would normally have expected the reverse -- i.e., problems with some QT based applications but no problems in MPEG Streamclip as adaptive PCM is usually a "conversion" compatible but not always an "edit" compatible format for Apple applications. Would still like to run my own tests to see if I can duplicate your problem on my system(s) as the question of the source of the problem remains open at this time.
I'm using ilife 09 with imovie updated regularly. The reason I said it wasn't relevant was because the streamclip had no sound in QT so no need to try imovie.
Your reasoning is fine as far as it goes but using iMovie '09 opens the door for native editing in DV and AIC for higher video quality (as already mentioned), as well as, H.264 with unrestricted data rates, Motion JPEG and Photo JPEG for medium quality video compression to medium size files, and/or MPEG-4 and H.264 with restricted data rates for lower quality but much smaller editing files. It also restricts you from using the Animation codec which is otherwise one of my favorite intermediate compression formats (which, if Apple hasn't fixed the problem, imports to iMovie '08/'09 but only exports as a blank black screen). Basically this means you have more conversion options for editing natively in iMovie having different video data rates which, in turn, means you can balance the editing file size against preserved quality as may be needed for different iMovie projects.
Can i please ask the following. The file sizes vary hugely but the quality appears the same after conversions. The AVI file is 17mb, the DV conversion in QT is 242mb and the MOV file created in imovie for the project is 49mb???? I oask because of disk space?
File size is directly proportional to the total data rate (i.e., amount of data per unit of time). All this means is that the more data you have per second in a file, the larger that file will be for a given duration. DV typically has a total data rate of about 28.5, 57.0, or about 112-114 mbps depending on the specific video and audio codecs in use. (The codecs are sometimes referred to as DV25, DV50, or DV100.) DV 25 is usually seen as DV video with DV audio (i.e., DV/DV) files which, depending on which Apple application/utility is measuring the file size, may appear to be twice its actual size. (I.e., some applications count the audio and video DV separately and add them together when it shouldn't.) In any case, DV video is not highly compressed and so the files are relatively large. Since the art of compression is actually the art of "throwing out data," DV files tend to retain more of the visual data from the source file than when converting to other, highly compressed video formats. Unfortunately, these files have very strict standards regarding the encoding matrix the playback dimensions and some applications can, in certain instances, actually lose the anamorphic flag required for proper playback/handling which can cause serious problems for some users. This is one of the reasons I tend to prefer the AIC codec which was specifically developed as an intermediate codec for both anamorphic SD, as well as, HD content. (I.e., it is a more versatile codec in today's world of multi-dimensioned multimedia files.) The other, is that AIC has a typical video data rate about 20-25% smaller than DV video with about the same level of quality.
In any event, to get back to your original question, the DIVX 5 codec is a more efficient compressor having a much lower video data rate than DV video. (Simple compare the video data rates of each to see what I mean here.) When you convert the DivX encoded data to DV you are trading data rates/file size for the retention of as much of the original visual quality as you can. If your current project (e.g., a project targeted as a 320x240 posting to the internet) does not require the retention of maximum quality, then you have the option of trying a more efficient codec with a lower data rate which would, of course, produce a smaller file for editing in iMovie. For instance, I would normally expect an MJPEG/AIFF file combination to be about 40-50% the size of your DV editing file. You may wish to try an MJPEG/AIFF or MJPEG/AAC editing project to see if you can detect much loss in visual quality and then decide which format is best for your particular work flow.
Hope this helps to understand what is going on here.