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| author | Cameron Cawley <ccawley2011@gmail.com> | 2018-10-13 00:06:39 +0100 |
|---|---|---|
| committer | Paul B Mahol <onemda@gmail.com> | 2018-10-26 13:39:25 +0200 |
| commit | 22238d0b9440cf55aafda42c60f4413514d4aeb8 (patch) | |
| tree | a406f18615ac7d99c232d797e229c5f3a9e7417b /libavcodec/pcm_tablegen.h | |
| parent | fb7925ba2fa10e1ecf63eb4bada268e25627a88d (diff) | |
| download | ffmpeg-22238d0b9440cf55aafda42c60f4413514d4aeb8.tar.gz | |
avcodec: Implement Archimedes VIDC encoder/decoder
Signed-off-by: Cameron Cawley <ccawley2011@gmail.com>
Diffstat (limited to 'libavcodec/pcm_tablegen.h')
| -rw-r--r-- | libavcodec/pcm_tablegen.h | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/libavcodec/pcm_tablegen.h b/libavcodec/pcm_tablegen.h index 7ce147f768..d8763abc40 100644 --- a/libavcodec/pcm_tablegen.h +++ b/libavcodec/pcm_tablegen.h @@ -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), @@ -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 */ |