Thursday, August 12, 2010

VideoQ&A: Problems with .AVI files from Canon camera

A while back I wrote about the .THM files that some cameras create along with their video files, which prompted this question:
I try to import .avi from my laptop on my canon .. i don't have .thm that comes with it .. Can I create an .thm ?? .. or how can i read any .avi if it does not from the canon itself...

First, a clarification: as far as I am aware, you do NOT need the .THM files to be able to open and play the .AVI files. The .THM files are there to help with searching and cataloging; for example Canon supplies a media browser application that uses these files. But the .AVI files should play fine without them.

If you have an .AVI or other video file that won't play on your computer, it's often because the video file uses a video compressor that you don't have installed in your system. You can often get these compressors as part of editing applications (like Premiere and Final Cut Pro), but they aren't the only ways to get them - and they may not support every camera out there either!

I would first go to the support area of the cameras manufacturer, and download and install any software that the manufacturer provides for the camera that created the files. It's possible that they will provide the compressor that the camera uses as part of that software package.

Alternatively, a hunt around the internet may find help, though different cameras use different compressors, so what works for one camera, may not work for another. Several owners of Canon PowerShot cameras that had problems playing .AVI files on their PCs seem to have found success with Morgan Multimedia's M3JPEGV3. They offer a 60 day free trial, so you can see if it works for you before spending money, but try the manufacturers software first

Morgan Morgan M-JPEG codec V3
NotesOnVideo: Canon .THM files


Zingaro said...

Hi Micheal.
Though I'm sure your post is useful and well-researched, it doesn't answer the user's question. You don't need the .THM files to watch .AVI files on your laptop, that's true. But you DO need them to watch video on the Canon camera. The user is trying to import .AVIs onto his Canon, and wonders whether he can create a .THM. I've just discovered that .THM are actually just a 160x120 JPEG, so technically, it should be possible, but it's not quite as simple as that, and the JPEG has to fit certain specific requirements that I haven't figure out yet. So technically it should be possible but no luck yet.

Michael Murie said...

IHmm...interesting; I may have misinterpreted what the user was trying to do.

If you want to put a movie file back on the camera, I believe that you can just make a copy of another .THM file, and rename it. However, you have to have a video file that is the same format as the files the camera creates, and that might be easier said than done.

But if you just have a file created by the camera, and want to put it back on the camera and don't have the .THM for it, make a copy of another .THM from the camera and rename it.

Unknown said...

I had a similar problem with the camera not showing JPEGs uploaded from a computer.
I discovered that: the sizes cannot be bigger than those of pictures taken by the camera, the sizes must be multiple of 4, and the JPEG must contains EXIF information.
I wrote a simple Perl program to convert the JPEG in a format supported by the camera and now I can upload whatever I want. Very useful when I travel to keep maps and timetables on the camera.
I wouldn't be surprised if the AVI limitations are the same of JPEG (max size and size multiple of 4)