From 514e0831aef4d487cf7b4a53c7fbb24222bc5634 Mon Sep 17 00:00:00 2001
From: Michael Niedermayer <michaelni@gmx.at>
Date: Thu, 6 Jul 2006 15:28:17 +0000
Subject: [PATCH] noise bitstream filter add priv_data field to
 AVBitStreamFilterContext

Originally committed as revision 5644 to svn://svn.ffmpeg.org/ffmpeg/trunk
---
 libavcodec/allcodecs.c        |  1 +
 libavcodec/avcodec.h          |  3 +++
 libavcodec/bitstream_filter.c | 32 ++++++++++++++++++++++++++++++--
 3 files changed, 34 insertions(+), 2 deletions(-)

diff --git a/libavcodec/allcodecs.c b/libavcodec/allcodecs.c
index 11d765093a..81e5204a41 100644
--- a/libavcodec/allcodecs.c
+++ b/libavcodec/allcodecs.c
@@ -664,5 +664,6 @@ PCM_CODEC(CODEC_ID_ADPCM_SBPRO_2, adpcm_sbpro_2);
 
     av_register_bitstream_filter(&dump_extradata_bsf);
     av_register_bitstream_filter(&remove_extradata_bsf);
+    av_register_bitstream_filter(&noise_bsf);
 }
 
diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
index 1af9901999..ccf4f5d1b8 100644
--- a/libavcodec/avcodec.h
+++ b/libavcodec/avcodec.h
@@ -2573,6 +2573,7 @@ extern AVCodecParser aac_parser;
 
 
 typedef struct AVBitStreamFilterContext {
+    void *priv_data;
     struct AVBitStreamFilter *filter;
     AVCodecParserContext *parser;
     struct AVBitStreamFilterContext *next;
@@ -2581,6 +2582,7 @@ typedef struct AVBitStreamFilterContext {
 
 typedef struct AVBitStreamFilter {
     const char *name;
+    int priv_data_size;
     int (*filter)(AVBitStreamFilterContext *bsfc,
                   AVCodecContext *avctx, const char *args,
                   uint8_t **poutbuf, int *poutbuf_size,
@@ -2600,6 +2602,7 @@ void av_bitstream_filter_close(AVBitStreamFilterContext *bsf);
 
 extern AVBitStreamFilter dump_extradata_bsf;
 extern AVBitStreamFilter remove_extradata_bsf;
+extern AVBitStreamFilter noise_bsf;
 
 
 /* memory */
diff --git a/libavcodec/bitstream_filter.c b/libavcodec/bitstream_filter.c
index 8cc75a976b..50fd47caac 100644
--- a/libavcodec/bitstream_filter.c
+++ b/libavcodec/bitstream_filter.c
@@ -15,6 +15,7 @@ AVBitStreamFilterContext *av_bitstream_filter_init(const char *name){
         if(!strcmp(name, bsf->name)){
             AVBitStreamFilterContext *bsfc= av_mallocz(sizeof(AVBitStreamFilterContext));
             bsfc->filter= bsf;
+            bsfc->priv_data= av_mallocz(bsf->priv_data_size);
             return bsfc;
         }
         bsf= bsf->next;
@@ -23,6 +24,7 @@ AVBitStreamFilterContext *av_bitstream_filter_init(const char *name){
 }
 
 void av_bitstream_filter_close(AVBitStreamFilterContext *bsfc){
+    av_freep(&bsfc->priv_data);
     av_parser_close(bsfc->parser);
     av_free(bsfc);
 }
@@ -31,6 +33,8 @@ int av_bitstream_filter_filter(AVBitStreamFilterContext *bsfc,
                                AVCodecContext *avctx, const char *args,
                      uint8_t **poutbuf, int *poutbuf_size,
                      const uint8_t *buf, int buf_size, int keyframe){
+    *poutbuf= (uint8_t *) buf;
+    *poutbuf_size= buf_size;
     return bsfc->filter->filter(bsfc, avctx, args, poutbuf, poutbuf_size, buf, buf_size, keyframe);
 }
 
@@ -39,8 +43,6 @@ static int dump_extradata(AVBitStreamFilterContext *bsfc, AVCodecContext *avctx,
                      const uint8_t *buf, int buf_size, int keyframe){
     int cmd= args ? *args : 0;
     /* cast to avoid warning about discarding qualifiers */
-    *poutbuf= (uint8_t *) buf;
-    *poutbuf_size= buf_size;
     if(avctx->extradata){
         if(  (keyframe && (avctx->flags2 & CODEC_FLAG2_LOCAL_HEADER) && cmd=='a')
            ||(keyframe && (cmd=='k' || !cmd))
@@ -85,12 +87,38 @@ static int remove_extradata(AVBitStreamFilterContext *bsfc, AVCodecContext *avct
     return 0;
 }
 
+static int noise(AVBitStreamFilterContext *bsfc, AVCodecContext *avctx, const char *args,
+                     uint8_t **poutbuf, int *poutbuf_size,
+                     const uint8_t *buf, int buf_size, int keyframe){
+    int amount= args ? atoi(args) : 10000;
+    unsigned int *state= bsfc->priv_data;
+    int i;
+
+    *poutbuf= av_malloc(buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
+
+    memcpy(*poutbuf, buf, buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
+    for(i=0; i<buf_size; i++){
+        (*state) += (*poutbuf)[i] + 1;
+        if(*state % amount == 0)
+            (*poutbuf)[i] = *state;
+    }
+    return 1;
+}
+
 AVBitStreamFilter dump_extradata_bsf={
     "dump_extra",
+    0,
     dump_extradata,
 };
 
 AVBitStreamFilter remove_extradata_bsf={
     "remove_extra",
+    0,
     remove_extradata,
 };
+
+AVBitStreamFilter noise_bsf={
+    "noise",
+    sizeof(int),
+    noise,
+};