The version 10 updates of both the SWF and FLV specs are available for your inspection:
Here are some of the things added, changed, or corrected:
- new DefineBitsJPEG4 tag (90), with deblocking filter
- new DefineFont4 tag (91)
- described how to embed Speex into SWF and FLV
- described how to embed XMP metadata in FLV
- new flags in the FileAttributes tag describe whether a SWF requires the new ‘gpu’ or ‘direct’ WMODEs (only useful when running a SWF in a standalone player where there is no encompassing HTML to specify WMODE)
- new flag in DefineShape4 describes whether the shape uses fill winding rule
- rearranged some chapters to (hopefully) make the SWF spec flow better
- revised DefineBitsJPEG2 and DefineBitsJPEG3 to mention how they can be used to store GIF and PNG data as well as JPEG (as can the new DefineBitsJPEG4 tag; yes, the tag names are a bit misleading, but they’re a bit too entrenched to be changed now)
- revised description of the Flash Screen Video v2 codec format
- in F4V, several signed values were incorrectly marked as unsigned
- fixed description of Flash ADPCM (initial predictors are signed, not unsigned; block size was off by 1)
- both documents now thoroughly describe which parameters (channels, bit resolution, sample rate) are fixed or flexible depending on the audio codec
- the FileAttributes tag came about in SWF 8 rather than SWF 1
- fixed the FileAttributes tag, which specifies a Metadata data structure — not a SymbolClass — with the hasMetadata flag
- in ButtonRecord and PlaceObject3, list the correct codes for the difference, add, and subtract blend modes
- PlaceObject3 tag description was missing a bitmap caching byte (should have been there since SWF 8 spec)
- in FillStyle, a GradientMatrix is also present for fill style 0×13
- SWF spec now uses “opacity” instead of “transparency” in many places in order to more accurately describe blending behavior
- clarified the maximum length of a SWF file
- fixed several examples
- fixed numerous inconsistencies in the Actions chapter
Thanks to Michael, Baptiste, both Benjamins, Bobby, Amol, Cody, Matthew, Romi, and anyone else I might have missed who also offered corrections and suggestions for improvements.

How about some RTMP protocol specifications, please?
thank you for this, works great on my centos64 box!
Cool! Does that free up resources to get the 32-bit Linux platforms (Ubuntu for PPC, Yellow Dog Linux for PPC) going again?
Nice to see so good informations. Very good blog.
Thank you. Great work.