extract from
http://youmakemedia.com/2007/03/26/ffmpegx-tip-codec-type-mismatch/
Thanks to the author : Chris
ffmpegX is one of the most useful tools in a content producer’s arsenal. It’s fast, easy, and powerful beyond belief. Unfortunately, it has the occasional error that may make you scream! When a client needs a video in a certain format and you are getting error messages, it isn’t fun.
One such error that I frequently encounter (especially when converting files to Flash Video) is this one: Codec type mismatch for mapping #0.0 -> #0.0 See, normally video comes before audio in the layout and organization of a multimedia file. Sometimes though (and it’s happening more frequently), codec creators are switching things up for a bit of fun. They’re putting the audio first. I can only assume it’s somehow related to compression - but this switch causes ffmpegX to freak out and cease encoding. Luckily, this is a one check-box fix. Simply open your file and navigate to the audio tab. Then check the box titled “Invert Mapping”. This will let ffmpegX know about the alternate structure of your file, and make the appropriate changes. Below is a screenshot that highlights the audio tab with Invert Mapping selected. Traditional FFmpeg, for *NIX platforms, offers this feature as well, albeit in a more complex manner. From the official documentation: You can encode to several formats at the same time and define a mapping from input stream to output streams: ffmpeg -i /tmp/a.wav -ab 64k /tmp/a.mp2 -ab 128k /tmp/b.mp2 -map 0:0 -map 0:0 Converts a.wav to a.mp2 at 64 kbits and to b.mp2 at 128 kbits. ‘-map file:index’ specifies which input stream is used for each output stream, in the order of the definition of output streams.