[MPlayer-users] thumbnail from a SWF / VP6

[Alexander Bokovikov]

You're not right in your understanding of SWF file format.

In fact it embeds just the same frame sequence as FLV file contains. The 
only difference is that audio is separated from video as different SWF tags. 
Moreover, it is obvious, that each frame can't contain a keyframe, otherwise 
what would be VP6 codec used for? Keyframe is just a kind of JPEG, don't you 
know? Any MPEG-style video codec's main goal is just to insert as many 
interfarames as it can to maintain good picture quality.

It is another aspect of this issue, that FlashPlayer "knows" how to show 
N-th frame, when you tell him to go to a frame N, regardless to the video 
portion kind (interframe/keyframe) it contains. To resolve your issue I'd 
suggest to use a software tool, playing with SWF, but not a tool, playing 
video. If you wish to know more about this topic, please write to me 
directly.


> thanks for the response.  as i understand it, SWF is all key frames,
> it's not like an FLV where there are key frames and interframes, but i
> could be wrong.  i took a sample of 20 frames and they're all equally
> scrambled.  any thoughts?
>
>> It's possible that the frame you're skipping to isn't a key frame,
>> and thus doesn't have a full picture to decode. Try taking a sample
>> of about 10-20 frames, see if you can get a decent frame out of any
>> of them.