From e8e474359144fce0335f27a4f22f22d8f5d5be40 Mon Sep 17 00:00:00 2001 From: Stefan Gehrer Date: Wed, 25 Jun 2008 14:14:58 +0000 Subject: [PATCH] make ModeAlphabet read-only and use a custom mode alphabet only locally in unpack_modes() Originally committed as revision 13964 to svn://svn.ffmpeg.org/ffmpeg/trunk --- libavcodec/vp3.c | 24 +++++++++++++++--------- 1 file changed, 15 insertions(+), 9 deletions(-) diff --git a/libavcodec/vp3.c b/libavcodec/vp3.c index 1366666c2d..3c06fe4d09 100644 --- a/libavcodec/vp3.c +++ b/libavcodec/vp3.c @@ -172,11 +172,8 @@ typedef struct Vp3Fragment { #define MODE_COPY 8 /* There are 6 preset schemes, plus a free-form scheme */ -static int ModeAlphabet[7][CODING_MODE_COUNT] = +static const int ModeAlphabet[6][CODING_MODE_COUNT] = { - /* this is the custom scheme */ - { 0, 0, 0, 0, 0, 0, 0, 0 }, - /* scheme 1: Last motion vector dominates */ { MODE_INTER_LAST_MV, MODE_INTER_PRIOR_LAST, MODE_INTER_PLUS_MV, MODE_INTER_NO_MV, @@ -877,6 +874,7 @@ static int unpack_modes(Vp3DecodeContext *s, GetBitContext *gb) int current_macroblock; int current_fragment; int coding_mode; + int custom_mode_alphabet[CODING_MODE_COUNT]; debug_vp3(" vp3: unpacking encoding modes\n"); @@ -896,12 +894,17 @@ static int unpack_modes(Vp3DecodeContext *s, GetBitContext *gb) if (scheme == 0) { debug_modes(" custom mode alphabet ahead:\n"); for (i = 0; i < 8; i++) - ModeAlphabet[scheme][get_bits(gb, 3)] = i; + custom_mode_alphabet[get_bits(gb, 3)] = i; } - for (i = 0; i < 8; i++) - debug_modes(" mode[%d][%d] = %d\n", scheme, i, - ModeAlphabet[scheme][i]); + for (i = 0; i < 8; i++) { + if(scheme) + debug_modes(" mode[%d][%d] = %d\n", scheme, i, + ModeAlphabet[scheme-1][i]); + else + debug_modes(" mode[0][%d] = %d\n", i, + custom_mode_alphabet[i]); + } /* iterate through all of the macroblocks that contain 1 or more * coded fragments */ @@ -921,8 +924,11 @@ static int unpack_modes(Vp3DecodeContext *s, GetBitContext *gb) /* mode 7 means get 3 bits for each coding mode */ if (scheme == 7) coding_mode = get_bits(gb, 3); + else if(scheme == 0) + coding_mode = custom_mode_alphabet + [get_vlc2(gb, s->mode_code_vlc.table, 3, 3)]; else - coding_mode = ModeAlphabet[scheme] + coding_mode = ModeAlphabet[scheme-1] [get_vlc2(gb, s->mode_code_vlc.table, 3, 3)]; s->macroblock_coding[current_macroblock] = coding_mode;