FFmpeg: AVI to Rawvideo

[David_UK]

Using ffmpeg, I have previously converted .flv (with sound) to rawvideo and can play in WMP & WMM:
However, I just tried to convert this .avi (no sound) to rawvideo and although the output codec is the same, cannot play it in WMP or WMM (Windows Media Player cannot play the file. The Player might not support the file type or a required codec might not be installed on your computer.):

E:>ffmpeg_13778 -i test.avi -vcodec rawvideo -t 2 testout.avi

FFmpeg version Sherpya-r13778, Copyright (c) 2000-2008 Fabrice Bellard, et al.
libavutil version: 49.7.0
libavcodec version: 51.57.2
libavformat version: 52.16.0
libavdevice version: 52.0.0
libavfilter version: 0.0.0
built on Jun 16 2008 13:00:49, gcc: 4.2.3

Input #0, avi, from 'test.avi':
Duration: 00:00:05.20, start: 0.000000, bitrate: 2181 kb/s
Stream #0.0: Video: msmpeg4v2, yuv420p, 512x512, 15.00 tb(r)
Output #0, avi, to 'testout.avi':
Stream #0.0: Video: rawvideo, yuv420p, 512x512, q=2-31, 200 kb/s, 15.00 tb(c)

Stream mapping:
Stream #0.0 -> #0.0
Press [q] to stop encoding
frame= 30 fps= 1 q=0.0 Lsize= 11526kB time=2.00 bitrate=47211.5kbits/s
video:11520kB audio:0kB global headers:0kB muxing overhead 0.054253%

Any suggestions why there is a difference - possibly to do with the lack of audio?
Thanks.

[Placio74]

... cannot play it in WMP or WMM (Windows Media Player cannot play the file. The Player might not support the file type or a required codec might not be installed on your computer.)...

And You have installed decoder for I420?

[David_UK]

And You have installed decoder for I420?

Do I need to? Given that the other i420 rawvideo files play properly and Gspot indicates the codec as identical for both files?

[vhelp]

I'm only guessing here.. but maybe its YV12 and not i420. There's the Helix yv12 codec you can download.

I remember having this problem a long time ago, (when I was building raw codec writer/reader in pascal) and then learnt that there are two, 4:2:0 sampling formats: i420 and YV12 and that the only difference between the two was with the way/order the chroma was placed.

The helix codec opens both i420 and yv12 formats.

DOWNLOAD: helix v1.2 -- 103kb

-vhelp 4862

[David_UK]

vhelp

That's done it! Amazing that you should know. Thanks.
I've only ever used Gspot to identify codecs - is there any way to distinguish these two?

[vhelp]

Yeah, no problem

But I can't take the credit.. I mean.., I seen celtic_druid mention Helix many the times. I'm pretty sure that the idea came to me thanks to him.

Regarding this codec reading tools..

It is possible that some codecs will share the same fourcc string, othwise these tools are using other methods in addition to standard ones, such as reading the JUNK / COMMENT area of avi's / MPEG's to find the comment or signature string that identifies the given source file. So, gspot could have been looking in is usual way and found the first identifier and reported back right away. It shouldn't have to double-check it for alternates if it gets right the first time. I know its a bit confusing but thats how it is.

The moral of all this is that, if in doubt, double-check!

I am glad you met with success!

EDIT:
Over in the tools section there should be a app called codec swaper that you can D/L. Its pretty self explanitory. Run it and it will report all your codecs in listing and you can see all the fourcc or color space / formats available to you. When you want to disable a given codec (because you might have two same codecs on your machine) you can double-click it or drag it down into the bottom pane and vis-versa.

I even wrote something (crude) in pascal that does something similar, only it just lists all the codecs -- limited only to AVI however.

-vhelp 4873