version 10:
- av_strnstr
- support ID3v2 tags in ASF files
+- reference-counting for AVFrame and AVPacket data
+- avconv now fails when input options are used for output file
+ or vice versa
+- new avconv options -filter_script and -filter_complex_script, which allow a
+ filtergraph description to be read from a file
+- uniform options syntax across all filters
+- new interlace filter
version 9: