Creative Media Format (.CMV) proof-of-concept encoder

[plexx]

Hi everyone,

There are quite some people who've bought a Zen MX and use Linux. These people are out of luck when it comes to putting video on their device, since it uses the proprietary CMV format. I've documented the format here:
http://wiki.multimedia.cx/index.php?title=CMV

And I've written a proof-of-concept (glue and ducktape) solution for encoding CMV. Its pretty ugly and uses ffmpeg to actually rip the content of a video. Currently there is a windows batch-file which starts ffmpeg and after that my custom java app for creating the actual CMV file. It works, but there is little control over bitrate and quality, and it creates a lot of overhead (temporary files) etc...

Unfortunately I've little time on my hands to turn this into a proper C application. So, i was wondering if someone with more C/Linux skills would be interested into turning this into a proper application, with or without my help. (Or if someone knows some place where there would people interested in doing this.)

I've attached the application including source (but without the required ffmpeg) free to do with whatever you want.

Regards,
Vincent

cmvencoder.zip

[Baldrick]

Ask in http://forum.doom9.org also. Lots of programmers over there.

[zacatron]

Hi plexx. thanks for you work. I tried to convert a xdiv .avi video to CMV with your application. Everything seems ok, but I play the .CMV in the Zen MX, it doesn't plays anything.. no sound, no image. If I open the .cmv with BsPlayer I get the sound, but no image.

What am I doing wrong? Thx

[plexx]

Hi zacatron,

Hmm.. I haven't tested it extensively, however, important is to have a rather recent version of FFMPEG. The filesize should approximate about 10MB per minute. Also your java version should be pretty recent (1.5 +, 1.4 might work). Other than that I wouldn't know. Does the zen MX quit playing the video or does it play it but is it all black and silent?

BsPlayer will see the CMV as a WAV file (because that is what the first part of the file is). If the CMV is not too big you could send/attach it and I can take a look.

Regards,
Vincent

[viraptor]

If only I knew about it before I was looking for the same tool 2 months ago... and decided to write one yesterday. It's just a simple python script that uses ffmpeg and imagemagik: http://bitbucket.org/viraptor/cmv_encoder/wiki/Home So now we've got 2 encoders - I guess it's better to have 2 options than none

[brugh]

Hi zacatron,

Hmm.. I haven't tested it extensively, however, important is to have a rather recent version of FFMPEG. The filesize should approximate about 10MB per minute. Also your java version should be pretty recent (1.5 +, 1.4 might work). Other than that I wouldn't know. Does the zen MX quit playing the video or does it play it but is it all black and silent?

BsPlayer will see the CMV as a WAV file (because that is what the first part of the file is). If the CMV is not too big you could send/attach it and I can take a look.

Regards,
Vincent

OMG! 10MB/minute? that means my 'The Unit' episodes of 50 minutes each would take 500MB on the device while they're only 200mb on my mediacenter with a resolution that is less than half that of the original??? i'm starting to regret buying the MX.. is there anything i can do with jpeg quality or smt to shrink it?

as for your program, i'm very grateful that you built it! i'm using linux so the creative suite is not an option. but while the ffmpeg part works fine, i get an error when it runs the java bit. i get:

Transcoding video...
.Exception in thread "main" javax.imageio.IIOException: Invalid argument to native writeImage
at com.sun.imageio.plugins.jpeg.JPEGImageWriter.write Image(Native Method)
at com.sun.imageio.plugins.jpeg.JPEGImageWriter.write OnThread(JPEGImageWriter.java:1055)
at com.sun.imageio.plugins.jpeg.JPEGImageWriter.write (JPEGImageWriter.java:357)
at CMVEncoder.transcodeJPEG(CMVEncoder.java:163)
at CMVEncoder.encode(CMVEncoder.java:43)
at CMVEncoder.main(CMVEncoder.java:35)

i'm not into java much so i dont know where to look for the error. could you line out what the program should do? or am i just missing some library or something?

[brugh]

If only I knew about it before I was looking for the same tool 2 months ago... and decided to write one yesterday. It's just a simple python script that uses ffmpeg and imagemagik: http://bitbucket.org/viraptor/cmv_encoder/wiki/Home So now we've got 2 encoders - I guess it's better to have 2 options than none

i tried yours too and it actually creates cmv files. but i encoded a 45 minute movie and ended up with a 920mb file.. that's horribly big isn't it? my device only has 8gb of space. is that normal? or is there something i can do to shrink the size to a normal mp4 player size like 100mb/hour..

why on earth did creative come up with this format.. why not just play 264 files like any other mp4 device.

[BigBanana]

If you use the Creative Centrale program transfer utility, it does the conversion for you! (Windows).
At least it does from mp4 format...

Is there a version that runs under linux?

[irpap]

Hello (and sorry for necroing this)

Thanks for your encoder plexx, I ran it with an mp4 as input, and I got a cmv with working audio but no video.
I wanted to ask the people who have made this work successfully, which version of ffmpeg they used (i'm using the latest), and what type of input file (not sure if that would make any difference) if you remember?

Thanks