diff options
author | Alex Converse <alex.converse@gmail.com> | 2010-07-13 01:35:43 +0400 |
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committer | Alex Converse <alex.converse@gmail.com> | 2010-07-13 01:35:43 +0400 |
commit | 93c6ff6c8c2ea39d6b4173efc9732010c51d0703 (patch) | |
tree | 8300a53993e568a4a5bbdcf2a0de4ac2d85be981 /libavcodec/aacdec.c | |
parent | f07c9895e0737f0f6a9874f0494f92a59c085f20 (diff) |
aacdec: Use a LUT to generate CCE scale.
Originally committed as revision 24224 to svn://svn.ffmpeg.org/ffmpeg/trunk
Diffstat (limited to 'libavcodec/aacdec.c')
-rw-r--r-- | libavcodec/aacdec.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/libavcodec/aacdec.c b/libavcodec/aacdec.c index 19e7783dbf..9214c18b91 100644 --- a/libavcodec/aacdec.c +++ b/libavcodec/aacdec.c @@ -1454,6 +1454,13 @@ static int decode_cpe(AACContext *ac, GetBitContext *gb, ChannelElement *cpe) return 0; } +static const float cce_scale[] = { + 1.09050773266525765921, //2^(1/8) + 1.18920711500272106672, //2^(1/4) + M_SQRT2, + 2, +}; + /** * Decode coupling_channel_element; reference: table 4.8. * @@ -1484,7 +1491,7 @@ static int decode_cce(AACContext *ac, GetBitContext *gb, ChannelElement *che) coup->coupling_point += get_bits1(gb) || (coup->coupling_point >> 1); sign = get_bits(gb, 1); - scale = pow(2., pow(2., (int)get_bits(gb, 2) - 3)); + scale = cce_scale[get_bits(gb, 2)]; if ((ret = decode_ics(ac, sce, gb, 0, 0))) return ret; |