Problem using avconv to convert .mp4 to .webm

Question

I'll try to describe my situation:

I have an android phone makes video in mp4 format. I like to share this video on my web page and jwplayer. Such that operates well. I use one script to make all and all works fine. I use to convert the file in webm,and Inserting in jwplayer with this type of embedding code:

 <div id="player" align="center">
<script src="jwplayer.js" type="text/javascript"></script>

 <script type="text/javascript"> jwplayer("player").setup({
     height: 270,
     image: "thumb.png",
     levels: [
         {file: 'file.mp4', type: 'video/mp4' },
         {file: 'file.webm', type: 'video/webm' },
     ],
     modes: [
         { type: 'html5' },
         { type: 'flash', src: 'player.swf' }
     ],
     width: 480 }); </script></div>

to convert from mp4 to webm i use simply this command:

avconv -i "$file".mp4 "$file".webm

OK! Now the problem is with my new photo camera. My pentax makes video in AVI and in this case to embedding with my jwplayer I need one mp4 and one webm file.

OK I use this command:

avconv -i "$videoname".AVI -c:v libx264 -crf 23 -c:a libfaac -b:a 192k "$videoname".mp4

the results are positive.

Now if i use to convert this new mp4 in webm with:

avconv -i "$file".mp4 "$file".webm

the webm file doesn't work....

example ffprobe with the avi file:

$ ffprobe IMGP0129.AVI 
avprobe version 0.8.4-4:0.8.4-0ubuntu0.12.04.1, Copyright (c) 2007-2012 the Libav               
developers
  built on Nov  6 2012 16:51:33 with gcc 4.6.3
Input #0, avi, from 'IMGP0129.AVI':
  Duration: 00:00:44.64, start: 0.000000, bitrate: 27089 kb/s
    Stream #0.0: Video: mjpeg, yuvj420p, 1280x720, 30.08 tbr, 30.08 tbn, 30.08 tbc
    Stream #0.1: Audio: pcm_u8, 32000 Hz, 1 channels, u8, 256 kb/s

example of error message for the webm in output:

$ avconv -i output.mp4 out2.webm
avconv version 0.8.4-4:0.8.4-0ubuntu0.12.04.1, Copyright (c) 2000-2012 the Libav
developers
 built on Nov  6 2012 16:51:33 with gcc 4.6.3
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'output.mp4':
 Metadata:
   major_brand     : isom
   minor_version   : 512
   compatible_brands: isomiso2avc1mp41
   encoder         : Lavf53.21.0
 Duration: 00:00:04.99, start: 0.000000, bitrate: 2228 kb/s
   Stream #0.0(und): Video: h264 (Main), yuvj420p, 1280x720, 2193 kb/s, 30.01 fps,
30.01 tbr, 500k tbn, 60.01 tbc
   Stream #0.1(und): Audio: aac, 32000 Hz, mono, s16, 54 kb/s
Incompatible pixel format 'yuvj420p' for codec 'libvpx', auto-selecting format 'yuv420p'
[buffer @ 0x2345340] w:1280 h:720 pixfmt:yuvj420p
[avsink @ 0x2356540] auto-inserting filter 'auto-inserted scaler 0' between the filter
'src' and the filter 'out'
[scale @ 0x2343220] w:1280 h:720 fmt:yuvj420p -> w:1280 h:720 fmt:yuv420p flags:0x4
[libvpx @ 0x23468a0] v1.0.0
Output #0, webm, to 'out2.webm':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf53.21.0
    Stream #0.0(und): Video: libvpx, yuv420p, 1280x720, q=-1--1, 200 kb/s, 1k tbn,
30.01 tbc
    Stream #0.1(und): Audio: libvorbis, 32000 Hz, mono, s16
Stream mapping:
  Stream #0:0 -> #0:0 (h264 -> libvpx)
  Stream #0:1 -> #0:1 (aac -> libvorbis)
Press ctrl-c to stop encoding
**[webm @ 0x2344de0] Application provided invalid, non monotonically increasing dts to
**muxer in stream 0: 33 >= 33**
**strong text**av_interleaved_write_frame(): Invalid argument**

Any suggestions?

Answer 1

finally for some have interest, i use these commands to convert some type of video files:

avconv -i "$videoname".AVI -b 2048k -r 30 -c:a libmp3lame "$videoname".mp4
avconv -i "$videoname".AVI -c:v libx264 -ar 44100 -y "$videoname".flv
avconv -i "$videoname".mp4 -y "$videoname".webm

with these three steps i can embed correctly with my script.