[FFmpeg-devel] entropy coding in dvcpro

Roman V. Shaposhnik rvs
Tue Jan 6 23:59:07 CET 2009

On Tue, 2009-01-06 at 14:33 +0100, EVS Hardware Dpt wrote:
> Hello Roman,
> There is an ambiguity in the spec. Indeed the sentence you mentioned in your
> answer suggests that it is mandatory. But in the variable length coding
> section of the same spec one can read: "When the values of all of the
> remaining quantized coefficients are zero within a DCT block, the coding
> process is ended by adding the EOB (end of block) code word of 0110b
> immediately after the last code word." This last paragraph suggests that if
> the last ac quantized coefficients is non-zero, an EOB code words is not
> present.

Well, my experience with ISO language standards suggests that 
whenever you see 'shall' being used -- you can be pretty sure
that it is a prescriptive definition, not subject for interpretation.
And they are usually pretty rigid about the language.


More information about the ffmpeg-devel mailing list