[FFmpeg-devel] [PATCH 1/1] Add vpx range encoder support
MihirGore
mihirmvgore at gmail.com
Wed Mar 5 18:29:34 EET 2025
From: MihirGore23 <mihirvgore at outlook.com>
---
libavcodec/vpx_rac.h | 75 ++++++++++++++++++++++++++++++++++----------
1 file changed, 59 insertions(+), 16 deletions(-)
diff --git a/libavcodec/vpx_rac.h b/libavcodec/vpx_rac.h
index b158cc0754..f01358f71f 100644
--- a/libavcodec/vpx_rac.h
+++ b/libavcodec/vpx_rac.h
@@ -20,7 +20,7 @@
/**
* @file
- * Common VP5-VP9 range decoder stuff
+ * Common VP5-VP9 range encoder and decoder functions
*/
#ifndef AVCODEC_VPX_RAC_H
@@ -34,24 +34,25 @@
typedef struct VPXRangeCoder {
int high;
- int bits; /* stored negated (i.e. negative "bits" is a positive number of
- bits left) in order to eliminate a negate in cache refilling */
+ int bits;
const uint8_t *buffer;
const uint8_t *end;
unsigned int code_word;
int end_reached;
+ uint8_t *output_buffer; // Added for encoding
+ uint8_t *output_end; // Added for encoding
} VPXRangeCoder;
extern const uint8_t ff_vpx_norm_shift[256];
+
+/*Decoder Functions */
+
int ff_vpx_init_range_decoder(VPXRangeCoder *c, const uint8_t *buf, int buf_size);
-/**
- * returns 1 if the end of the stream has been reached, 0 otherwise.
- */
static av_always_inline int vpx_rac_is_end(VPXRangeCoder *c)
{
if (c->end <= c->buffer && c->bits >= 0)
- c->end_reached ++;
+ c->end_reached++;
return c->end_reached > 10;
}
@@ -64,7 +65,7 @@ static av_always_inline unsigned int vpx_rac_renorm(VPXRangeCoder *c)
c->high <<= shift;
code_word <<= shift;
bits += shift;
- if(bits >= 0 && c->buffer < c->end) {
+ if (bits >= 0 && c->buffer < c->end) {
code_word |= bytestream_get_be16(&c->buffer) << bits;
bits -= 16;
}
@@ -72,12 +73,6 @@ static av_always_inline unsigned int vpx_rac_renorm(VPXRangeCoder *c)
return code_word;
}
-#if ARCH_ARM
-#include "arm/vpx_arith.h"
-#elif ARCH_X86
-#include "x86/vpx_arith.h"
-#endif
-
#ifndef vpx_rac_get_prob
#define vpx_rac_get_prob vpx_rac_get_prob
static av_always_inline int vpx_rac_get_prob(VPXRangeCoder *c, uint8_t prob)
@@ -95,7 +90,6 @@ static av_always_inline int vpx_rac_get_prob(VPXRangeCoder *c, uint8_t prob)
#endif
#ifndef vpx_rac_get_prob_branchy
-// branchy variant, to be used where there's a branch based on the bit decoded
static av_always_inline int vpx_rac_get_prob_branchy(VPXRangeCoder *c, int prob)
{
unsigned long code_word = vpx_rac_renorm(c);
@@ -117,7 +111,6 @@ static av_always_inline int vpx_rac_get_prob_branchy(VPXRangeCoder *c, int prob)
static av_always_inline int vpx_rac_get(VPXRangeCoder *c)
{
unsigned int code_word = vpx_rac_renorm(c);
- /* equiprobable */
int low = (c->high + 1) >> 1;
unsigned int low_shift = low << 16;
int bit = code_word >= low_shift;
@@ -132,4 +125,54 @@ static av_always_inline int vpx_rac_get(VPXRangeCoder *c)
return bit;
}
+//Encoder Functions
+
+int ff_vpx_init_range_encoder(VPXRangeCoder *c, uint8_t *buf, int buf_size);
+
+static av_always_inline void vpx_rac_renorm_encoder(VPXRangeCoder *c)
+{
+ while (c->high < 0x10000) {
+ if (c->output_buffer < c->output_end) {
+ *c->output_buffer++ = c->code_word >> 24;
+ }
+ c->code_word <<= 8;
+ c->high <<= 8;
+ }
+}
+
+static av_always_inline void vpx_rac_put_prob(VPXRangeCoder *c, int bit, uint8_t prob)
+{
+ unsigned int low = 1 + (((c->high - 1) * prob) >> 8);
+ if (bit) {
+ c->code_word += low << 16;
+ c->high -= low;
+ } else {
+ c->high = low;
+ }
+ vpx_rac_renorm_encoder(c);
+}
+
+static av_always_inline void vpx_rac_put(VPXRangeCoder *c, int bit)
+{
+ unsigned int low = (c->high + 1) >> 1;
+ if (bit) {
+ c->code_word += low << 16;
+ c->high -= low;
+ } else {
+ c->high = low;
+ }
+ vpx_rac_renorm_encoder(c);
+}
+
+static av_always_inline void vpx_rac_flush(VPXRangeCoder *c)
+{
+ for (int i = 0; i < 4; i++) {
+ if (c->output_buffer < c->output_end) {
+ *c->output_buffer++ = c->code_word >> 24;
+ }
+ c->code_word <<= 8;
+ }
+}
+
#endif /* AVCODEC_VPX_RAC_H */
+
--
2.43.0
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