Trying to use ffmpeg to do a conversion (remux) over to mp4 container:

ffmpeg -i blah.avi -vcodec copy blah.mp4

This works to play the file everywhere except in a flash player I'm trying to embed on my site. If I re-encode the file then it works in the flash player:

ffmpeg -i blah.avi blah.mp4

This is fine but the processing resources and time is massive compared to just remuxing. I'm using ffmpeg 1.2 and the remux looks like this:

Code:
./ffmpeg -i myfile.avi -vcodec copy myfile.mp4 ffmpeg version N-51169-gcedf276 Copyright (c) 2000-2013 the FFmpeg developers   built on Mar 21 2013 05:12:00 with gcc 4.6 (Debian 4.6.3-1)   
configuration: --prefix=/root/ffmpeg-static/32bit --arch=x86_32 --extra-cflags='-m32 -I/root/ffmpeg-static/32bit/include -static' --extra-ldflags='-m32 -L/root/ffmpeg-static/32bit/lib -static' --extra-libs='-lxml2 -lexpat -lfreetype' --enable-static --disable-shared --disable-ffserver --disable-doc --enable-bzlib --enable-zlib --enable-postproc --enable-runtime-cpudetect --enable-libx264 --enable-gpl --enable-libtheora --enable-libvorbis --enable-libmp3lame --enable-gray --enable-libass --enable-libfreetype --enable-libopenjpeg --enable-libspeex --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-version3 --enable-libvpx   
libavutil      52. 22.100 / 52. 22.100   
libavcodec     55.  1.100 / 55.  1.100   
libavformat    55.  0.100 / 55.  0.100   
libavdevice    55.  0.100 / 55.  0.100   
libavfilter     3. 48.100 /  3. 48.100   
libswscale      2.  2.100 /  2.  2.100   
libswresample   0. 17.102 /  0. 17.102   
libpostproc    52.  2.100 / 52.  2.100 
[avi @ 0x9fff660] non-interleaved AVI 
Guessed Channel Layout for  Input Stream #0.1 : mono 
Input #0, avi, from 'myfile.avi':   Metadata:     encoder         : Lavf52.64.2   Duration: 00:00:10.40, start: 0.000000, bitrate: 409 kb/s     Stream #0:0: Video: h264 (Baseline) (H264 / 0x34363248), yuvj420p, 640x480, 10 fps, 10 tbr, 10 tbn, 30 tbc     Stream #0:1: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 8000 Hz, mono, s16, 128 kb/s Output #0, mp4, to 'myfile.mp4':   Metadata:     encoder         : Lavf55.0.100     Stream #0:0: Video: h264 ([33][0][0][0] / 0x0021), yuvj420p, 640x480, q=2-31, 10 fps, 10240 tbn, 10 tbc     Stream #0:1: Audio: aac ([64][0][0][0] / 0x0040), 8000 Hz, mono, s16, 128 kb/s Stream mapping:   Stream #0:0 -> #0:0 (copy)   Stream #0:1 -> #0:1 (pcm_s16le -> libvo_aacenc) Press [q] to stop, [?] for help [mp4 @ 0xa006ea0] pts has no value     Last message repeated 100 times frame=  101 fps=0.0 q=-1.0 Lsize=     350kB time=00:00:11.06 bitrate= 259.3kbits/s video:332kB audio:15kB subtitle:0 global headers:0kB muxing overhead 0.926809%
Anything I can do to get remux to work?