libopus: decode ambisonics with non-diegetic sources

Channel mapping 2 additionally supports a non-diegetic stereo track
appended to the end of a full-order ambisonics signal, such that the
total channel count is either
  (n + 1) ^ 2, or
  (n + 1) ^ 2 + 2
where n is the ambisonics order

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This commit is contained in:
Felicia 2017-02-06 15:49:36 -08:00 committed by Michael Niedermayer
parent 1a71df9bac
commit fcf3e06fe4
1 changed files with 4 additions and 2 deletions

View File

@ -373,10 +373,12 @@ av_cold int ff_opus_parse_extradata(AVCodecContext *avctx,
channel_reorder = channel_reorder_vorbis;
} else if (map_type == 2) {
int ambisonic_order = ff_sqrt(channels) - 1;
if (channels != (ambisonic_order + 1) * (ambisonic_order + 1)) {
if (channels != ((ambisonic_order + 1) * (ambisonic_order + 1)) &&
channels != ((ambisonic_order + 1) * (ambisonic_order + 1) + 2)) {
av_log(avctx, AV_LOG_ERROR,
"Channel mapping 2 is only specified for channel counts"
" which can be written as (n + 1)^2 for nonnegative integer n\n");
" which can be written as (n + 1)^2 or (n + 1)^2 + 2"
" for nonnegative integer n\n");
return AVERROR_INVALIDDATA;
}
layout = 0;