From a514c60fd0952c0682aa544ee1e16445e6b7df84 Mon Sep 17 00:00:00 2001 From: Michael Giacomelli Date: Sun, 2 Sep 2007 03:28:49 +0000 Subject: Apparently, negative exponents are possible when decoding exponential VLC. Should fix occasional glitches that happened in files of all bitrates. git-svn-id: svn://svn.rockbox.org/rockbox/trunk@14571 a1c6a512-1295-4272-9138-f99709370657 --- apps/codecs/libwma/wmadata.h | 5 +++++ apps/codecs/libwma/wmadeci.c | 5 ++++- 2 files changed, 9 insertions(+), 1 deletion(-) (limited to 'apps') diff --git a/apps/codecs/libwma/wmadata.h b/apps/codecs/libwma/wmadata.h index cef945914a..63f922b6d6 100644 --- a/apps/codecs/libwma/wmadata.h +++ b/apps/codecs/libwma/wmadata.h @@ -1456,8 +1456,13 @@ const fixed64 pow_table[] = 0x14f2e7a000000LL,0x1781474000000LL,0x1a5f7f4000000LL,0x1d974de000000LL,0x2133a18000000LL }; +/*10^(index/16). We'll need to accomidate negative indicies too*/ const fixed32 pow_10_to_yover16[] ICONST_ATTR= { + /*16 negative indicies (-16 to -1)*/ +0x199a,0x1d90,0x2223,0x276c,0x2d86,0x3492,0x3cb5,0x461b,0x50f4,0x5d7c,0x6bf4,0x7caa,0x8ff6,0xa63e, +0xbff9, 0xddb0, + /*non-negative indicies*/ 0x10000,0x127a0,0x15562,0x18a39,0x1c73d,0x20db4,0x25f12,0x2bd09,0x3298b,0x3a6d9,0x4378b,0x4dea3, 0x59f98,0x67e6b,0x77fbb,0x8a8de,0xa0000,0xb8c3e,0xd55d1,0xf6636,0x11c865,0x148906,0x17b6b8,0x1b625b, 0x1f9f6e,0x248475,0x2a2b6e,0x30b25f,0x383bf0,0x40f02c,0x4afd4b,0x5698b0,0x640000,0x737a6b,0x855a26, diff --git a/apps/codecs/libwma/wmadeci.c b/apps/codecs/libwma/wmadeci.c index 3b81669d8f..8aa3620960 100644 --- a/apps/codecs/libwma/wmadeci.c +++ b/apps/codecs/libwma/wmadeci.c @@ -1110,6 +1110,9 @@ static int decode_exp_vlc(WMADecodeContext *s, int ch) fixed32 v, max_scale; fixed32 *q,*q_end; + /*accommodate the 16 negative indices */ + fixed32 *pow_10_to_yover16_ptr = &pow_10_to_yover16[16]; + band_ptr = s->exponent_bands[s->frame_len_bits - s->block_len_bits]; ptr = band_ptr; q = s->exponents[ch]; @@ -1142,7 +1145,7 @@ static int decode_exp_vlc(WMADecodeContext *s, int ch) /* NOTE: this offset is the same as MPEG4 AAC ! */ last_exp += code - 60; /* XXX: use a table */ - v = pow_10_to_yover16[last_exp]; + v = pow_10_to_yover16_ptr[last_exp]; if (v > max_scale) { max_scale = v; -- cgit v1.2.3