does anyone know of an easy way to change the frame rate tag in an avi file without having to recopy the entire file? i've been capturing from 16mm film to an avi file at 2048x1536 so the files are very large. the software, ic capture, is capturing from an industrial camera with a frame rate of 10fps. the software uses this frame rate in the avi file. problem is that i'm not actually capturing at 10fps. yes, the camera is sending at 10fps, but i'm using a trigger to capture frames only when cleanly seated in a projector gate. that means that my file's frame rate should have nothing to do with the camera's frame rate. the file's frame rate should match the film's intended projection speed, in this case, 24fps. for this reason, i need to try to change my file's rate. the file's are huge, though, so i'd like to be able to just change some data (in the header maybe?) to affect the change. using the file as-is causes final cut to read the file incorrectly. the only workaround i've come up with so faris to put it in mpeg streamclip, output it to an image sequence at 10fps, and re-import the frames into final cut. at 2048x1536 my file for ~1200ft of 16mm film is over 400gb. needless to say, all of this importing/exporting takes forever. that's why i'd like to find an alternative. thanks for any tips, BabaG

thanks n2! i'll try it tonight! edit: and the author has an, apparently, newer version (avifrate2009) on his site: edit2: just tried this utility and, while it did change the frame rate such that mpeg streamclip now reads the file as 24fps instead of 10fps, both final cut pro and quicktime player still read the file as the original 10fps. any thoughts? thanks, BabaG

i guess there is fps info stored in bitstream and qt player follows bitstream fps?

how would i find that and change it?

If FPS is stored in the bitstream, then it sound like only a complete recopy will do the job. I was curious about this, so I just tried using VirtualDub, change FPS on video menu, and Direct Stream copy. On playing in GOM media player and Media Player, it played at the amended frame rate, unfortunately quicktime would not play the file due to codec. If you have a lot of these files, it might be useful just to try it on a small cut, just mark start and end point and see if the resultant vid plays ok or not. VD is very fast in Direct Stream copy mode, the only real problem might be disk space. The only alternative is if you can find an "In-situ" bitstream FPS replacer. Gud Luk :) EDIT:- Also, VD can get rid of a lot of JUNK chunks that encoders put in an AVI file and so recopy may actuallyreduce the size of your files a little. :)

Sorry, dont know what a ref file is, but it sounds like it will again, just change the header (which already is established not to work for you). I again suggest that you try direct stream copying of just a minute or so of your source vid with the FPS mod, see if that solves your problem. It sounds like what quicktime etc is using is in the bitstream, embedded ALL the way through the 400GB vid, not just in the header. Any quick fix that can be done without scanning all 400GB, is not likely to work for you. IF you do the re-copy, and it works, then you know at least that it is a possible way around your prob, it will not take that long, anyway, mark eg 1 minute of the source (at orig FPS), do a direct stream copy, see how long it takes and multiply by orig FPS length of source, to get an estimate of recopy time. Also, find a link to a site that lists many, free file hosting sites, if you register an account with one of them, you will not have to wait for your attachment to go through moderation. Gud Luk :)

a ref file is like a frame-served file (ref for referenced). it's a pointer to the original avi but stored in qt format. tried saving through vdub and, oddly, qt player opens the new file and shows it to be 24fps. final cut, on the other hand, refuses to open it now. this, even after a simple direct stream copy. BabaG

Ok, dont know what to say. Check the re-timed VD mod is 24FPS in the header changer, also compare all other stuff shown by the header changer, anything else changed? Might be a good idea to attach or provide link to your screenshot, for someone more familiar with MAC stuff. I'd like to have a look too. Never tried this but, have you tried creating an *.avs script on a PC, link to the clip, with an "AssumeFPS(24.0)" in it and open over the network from your MAC. Dont know if the MAC would accept as an AVI, or perhaps there is another program that has some kind of proxy mode (VDUB does this) which can provide some kind of 'synthetic' AVI which might be acceptable to your MAC. VDUB creates '*.VDR' files for frame serving, (which may not work) but it also has another method (see proxyon.reg in VDUB frameserving, VD help, Processing, Frameserver). Have no idea if this will work over the network, but it may be worth a try. If not, maybe someone else with more knowledge on this could help. Gud Luk :)

sorry to have disappeared, StainlessS. ok. so, here's the solution. came from jan e. schotsman, maker of jes deinterlacer. great utility. everyone should have it if you have a mac. make a qt ref movie from the avi. open the ref movie in dumpster. there are four fields to edit for duration here. there is one other for 'sampDur'. under 'trak--->mdia--->minf--->stbl--->stts' you'll find: sampCnt sampDur sampCnt is the number of frames in the file. sampDur is fps. mine says 60, which corresponds to 10fps. per jan's fix, i changed that to 25, which corresponds to 24fps. you'll notice that 24fps is 10fps x 2.4 and that 25 = 60 / 2.4. now, we use a formula: sampCnt x sampDur to derive a number for duration. the file i'm looking at now has a samCnt of 17374. 17374 x 60 = 1042440 17374 x 25 = 434350 with these numbers, we now look for four fields containing the original value of 1042440. they are: 'mvhd--->duration' 'trak--->duration' 'trak--->edts--->elst--->Track Dur' 'mdia--->mdhd--->duration' each of these fields should contain the value 1042440. change that to 434350. make sure to click in another field after you make your last change so the value will be retained. then save. that's it. change five text fields and the file now opens as a 24fps file with the correct durations. in my case, making these five text entries (takes a minute or two), saved a three to four hour transcode. and, i have to do this dozens of times over saving, probably, hundreds of wasted hours. thanks to jan! these are simple files, in my case, picture only. i can imagine there might be additional issues with files containing audio or additional tracks. BabaG

OK, glad you sorted it out. Your explaination will I am sure help out others in the future. Be gud :)