X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=libavcodec%2Fpcm_tablegen.h;h=d8763abc40d1c7d608408a05f7a6bd0d60e25396;hb=18a567c369d74af5ef651b07c4c5615f5598616b;hp=7ce147f768b59d0a95d45298502b333215a0327b;hpb=50ae1f7e0ff1fa00236622415039f7e28d919a25;p=ffmpeg

diff --git a/libavcodec/pcm_tablegen.h b/libavcodec/pcm_tablegen.h
index 7ce147f768b..d8763abc40d 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 */