Stefan Sayer wrote: > in [1] 3. Protocol Operation the levels are described as having values > from 0 to 255, and referencing section 4 (which should be section 5): > > Each instance of this header contains a list of one-octet audio level > values (see Section 4). Such values indicate audio level on a 0 to > 255 scale where 0 is silence (i.e. same as omitting the corresponding > source id from the CSRC list) and 255 corresponds to a threshold > accepted by the mixer implementation as the maximum audio level that > a participant is likely to reach during a conference. > > while in section 5, the levels are described like in the comfort noise > specification with values 0..127 being 0..-127 dBov, where 0 would be > the maximum audio level threshold (not 255). Correct, thanks for pointing it out. > In [2], section 3, the MSB of the level field is in the Figure 1 of the > extension block: > > 0 1 2 > 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 > +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ > | ID | len=1 |0| level |V| reserved | > +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ > > So it may make sense to add this to Figure 2 in [1] as well : > 0 1 2 3 > 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 > +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ > | ID | len | level 1 | level 2 | level 3 ... > +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ > > Figure 2: Audio level indicators extension format > > would become: > 0 1 2 3 > 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 > +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ > | ID | len |0| level 1 |0| level 2 |0| level 3 ... > +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ > > Figure 2: Audio level indicators extension format > > (or, alternatively remove it from Figure 1 in [2], but I think that it > is good to have the MSB set to 0 in the Figure.) Agreed, the latter looks definitely better. -- Ciao, Enrico
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smime.p7s
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