Hi the Attached patch does the following: 1. cleanup packets so all have forward_ptr significantly improves extendability and simplifies stuff slightly larger overhead (~0.006% which is negligible) 2. split checksum into frame and syncpoint checksum simplification overhead changes by + 4byte for every packet >64kb (<0.006% worst case) overhead changes by - syncpoint size + 4 for every packet with dts_diff > 1sec overall this could even reduce the overhead, the worst case increase is also negligible 3. split index simplification for lavf muxer currently we just write the data out seek back and update the forward pointer, this is safe as long as the packet is < the io buffer size in lavf, if its larger we need to alloc&realloc a buffer and work within that or do 2 passes to find the forward ptr value, both are more messy index_ptr becomes unneccesary by this improves error resistance 4. always store chapter_start/len simplification 5. change file structure definion so extendability is restored 6. drop info streams i see no sense in them ... 7. dissalow width or height == 0 8. add leading coeff to the crc polynom -- Michael