diff options
Diffstat (limited to 'libavcodec/pcm_tablegen.h')
| -rw-r--r-- | libavcodec/pcm_tablegen.h | 59 |
1 files changed, 43 insertions, 16 deletions
diff --git a/libavcodec/pcm_tablegen.h b/libavcodec/pcm_tablegen.h index 438c2b9ea4..d8763abc40 100644 --- a/libavcodec/pcm_tablegen.h +++ b/libavcodec/pcm_tablegen.h @@ -3,20 +3,20 @@ * * Copyright (c) 2010 Reimar Döffinger <Reimar.Doeffinger@gmx.de> * - * This file is part of Libav. + * This file is part of FFmpeg. * - * Libav is free software; you can redistribute it and/or + * FFmpeg is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * - * Libav is distributed in the hope that it will be useful, + * FFmpeg is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public - * License along with Libav; if not, write to the Free Software + * License along with FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ @@ -36,6 +36,12 @@ #define BIAS (0x84) /* Bias for linear code. */ +#define VIDC_SIGN_BIT (1) +#define VIDC_QUANT_MASK (0x1E) +#define VIDC_QUANT_SHIFT (1) +#define VIDC_SEG_SHIFT (5) +#define VIDC_SEG_MASK (0xE0) + /* alaw2linear() - Convert an A-law value to 16-bit linear PCM */ static av_cold int alaw2linear(unsigned char a_val) { @@ -69,14 +75,30 @@ static av_cold int ulaw2linear(unsigned char u_val) return (u_val & SIGN_BIT) ? (BIAS - t) : (t - BIAS); } +static av_cold int vidc2linear(unsigned char u_val) +{ + int t; + + /* + * Extract and bias the quantization bits. Then + * shift up by the segment number and subtract out the bias. + */ + t = (((u_val & VIDC_QUANT_MASK) >> VIDC_QUANT_SHIFT) << 3) + BIAS; + t <<= ((unsigned)u_val & VIDC_SEG_MASK) >> VIDC_SEG_SHIFT; + + return (u_val & VIDC_SIGN_BIT) ? (BIAS - t) : (t - BIAS); +} + #if CONFIG_HARDCODED_TABLES #define pcm_alaw_tableinit() #define pcm_ulaw_tableinit() +#define pcm_vidc_tableinit() #include "libavcodec/pcm_tables.h" #else /* 16384 entries per table */ static uint8_t linear_to_alaw[16384]; static uint8_t linear_to_ulaw[16384]; +static uint8_t linear_to_vidc[16384]; static av_cold void build_xlaw_table(uint8_t *linear_to_xlaw, int (*xlaw2linear)(unsigned char), @@ -84,21 +106,21 @@ static av_cold void build_xlaw_table(uint8_t *linear_to_xlaw, { int i, j, v, v1, v2; - j = 0; - for(i=0;i<128;i++) { - if (i != 127) { - v1 = xlaw2linear(i ^ mask); - v2 = xlaw2linear((i + 1) ^ mask); - v = (v1 + v2 + 4) >> 3; - } else { - v = 8192; - } - for(;j<v;j++) { + j = 1; + linear_to_xlaw[8192] = mask; + for(i=0;i<127;i++) { + v1 = xlaw2linear(i ^ mask); + v2 = xlaw2linear((i + 1) ^ mask); + v = (v1 + v2 + 4) >> 3; + for(;j<v;j+=1) { + linear_to_xlaw[8192 - j] = (i ^ (mask ^ 0x80)); linear_to_xlaw[8192 + j] = (i ^ mask); - if (j > 0) - linear_to_xlaw[8192 - j] = (i ^ (mask ^ 0x80)); } } + for(;j<8192;j++) { + linear_to_xlaw[8192 - j] = (127 ^ (mask ^ 0x80)); + linear_to_xlaw[8192 + j] = (127 ^ mask); + } linear_to_xlaw[0] = linear_to_xlaw[1]; } @@ -111,6 +133,11 @@ static void pcm_ulaw_tableinit(void) { build_xlaw_table(linear_to_ulaw, ulaw2linear, 0xff); } + +static void pcm_vidc_tableinit(void) +{ + build_xlaw_table(linear_to_vidc, vidc2linear, 0xff); +} #endif /* CONFIG_HARDCODED_TABLES */ #endif /* AVCODEC_PCM_TABLEGEN_H */ |