From b26d3205835c3d66f655247d00044658d5e58e51 Mon Sep 17 00:00:00 2001 From: Vitor Sessak Date: Sun, 27 Jul 2008 22:22:51 +0000 Subject: Add a few comments pointing to the G.728 specification Originally committed as revision 14444 to svn://svn.ffmpeg.org/ffmpeg/trunk --- libavcodec/ra288.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'libavcodec/ra288.c') diff --git a/libavcodec/ra288.c b/libavcodec/ra288.c index 10f5ca715d..36d0b6097c 100644 --- a/libavcodec/ra288.c +++ b/libavcodec/ra288.c @@ -74,11 +74,13 @@ static void decode(RA288Context *ractx, float gain, int cb_coef) ractx->sb[x] = -scalar_product_float(ractx->sb + x + 1, ractx->sp_lpc, 36); - /* convert log and do rms */ + /* block 46 of G.728 spec */ sum = 32. - scalar_product_float(ractx->gain_lpc, ractx->lhist, 10); + /* block 47 of G.728 spec */ sum = av_clipf(sum, 0, 60); + /* block 48 of G.728 spec */ sumsum = exp(sum * 0.1151292546497) * gain; /* pow(10.0,sum/20)*f */ for (x=0; x < 5; x++) -- cgit v1.2.3