3gp Video Generation Failed!

[biologisch]

Hi!
I would like to creake a 3gp video for my mobile phone. But with Ubuntu 12 I got this message:

3gp Video Generation Failed!

But why? All other works fine.

Here are some more details from ffmpeg.log

ffmpeg version 0.8.3-6:0.8.3-7, Copyright (c) 2000-2012 the Libav developers
built on Aug 25 2012 13:25:50 with gcc 4.7.1
*** THIS PROGRAM IS DEPRECATED ***
This program is only provided for compatibility and will be removed in a future release. Please use avconv instead.
[image2 @ 0x836e840] max_analyze_duration reached

Seems stream 0 codec frame rate differs from container frame rate: 0.53 (53/100) -> 13.25 (53/4)
Input #0, image2, from '%03d-capture.jpg':
Duration: 00:01:13.58, start: 0.000000, bitrate: N/A
Stream #0.0: Video: mjpeg, yuvj420p, 320x240 [PAR 1:1 DAR 4:3], 0.53 fps, 13.25 tbr, 0.53 tbn, 0.53 tbc
Incompatible pixel format 'yuvj420p' for codec 'h263', auto-selecting format 'yuv420p'
[buffer @ 0x836ed80] w:320 h:240 pixfmt:yuvj420p
[avsink @ 0x83819c0] auto-inserting filter 'auto-inserted scaler 0' between the filter 'src' and the filter 'out'
[scale @ 0x8381e40] w:320 h:240 fmt:yuvj420p -> w:320 h:240 fmt:yuv420p flags:0x4
[h263 @ 0x836fcc0] The specified picture size of 320x240 is not valid for the H.263 codec.
Valid sizes are 128x96, 176x144, 352x288, 704x576, and 1408x1152.Try H.263+.
Output #0, 3gp, to '1-28959-r1-s1.3gp':
Stream #0.0: Video: h263, yuv420p, 320x240 [PAR 1:1 DAR 4:3], q=2-31, 200 kb/s, 90k tbn, 25 tbc
Stream mapping:
Stream #0.0 -> #0.0
Error while opening encoder for output stream #0.0 - maybe incorrect parameters such as bit_rate, rate, width or height

[biologisch]

Ok. I check it out with the "Valid sizes 352x288, 704x576" and it works fine with this resolutions.
But whats up to 320×240 or 640x480? Im a little bit worried about this limitations.

[bb99]

Kind of reads like PAL vs NTSC doesn't it? https://en.wikipedia.org/wiki/3GP_and_3G2 It's the specification for IMS and MMS; I wouldn't be concerned at all. I should add: it's been my experience that the 352*288 resolution seems to be much more compatible with MMS capable devices then the higher resolution. At the link two pieces of information jump out: GSM vs CDMA compatibility and the big-endian format.