AVBitStreamFilter (some thingy which can modify the bitstream like add or remove global headers or change the headers or ...)

Originally committed as revision 5643 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 96 insertions, 0 deletions

diff --git a/libavcodec/bitstream_filter.c b/libavcodec/bitstream_filter.c
new file mode 100644
index 0000000000..8cc75a976b
--- /dev/null
+++ b/libavcodec/bitstream_filter.c
@@ -0,0 +1,96 @@
+
+#include "avcodec.h"
+
+AVBitStreamFilter *first_bitstream_filter= NULL;
+
+void av_register_bitstream_filter(AVBitStreamFilter *bsf){
+    bsf->next = first_bitstream_filter;
+    first_bitstream_filter= bsf;
+}
+
+AVBitStreamFilterContext *av_bitstream_filter_init(const char *name){
+    AVBitStreamFilter *bsf= first_bitstream_filter;
+
+    while(bsf){
+        if(!strcmp(name, bsf->name)){
+            AVBitStreamFilterContext *bsfc= av_mallocz(sizeof(AVBitStreamFilterContext));
+            bsfc->filter= bsf;
+            return bsfc;
+        }
+        bsf= bsf->next;
+    }
+    return NULL;
+}
+
+void av_bitstream_filter_close(AVBitStreamFilterContext *bsfc){
+    av_parser_close(bsfc->parser);
+    av_free(bsfc);
+}
+
+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){
+    return bsfc->filter->filter(bsfc, avctx, args, poutbuf, poutbuf_size, buf, buf_size, keyframe);
+}
+
+static int dump_extradata(AVBitStreamFilterContext *bsfc, AVCodecContext *avctx, const char *args,
+                     uint8_t **poutbuf, int *poutbuf_size,
+                     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))
+           ||(cmd=='e')
+            /*||(? && (s->flags & PARSER_FLAG_DUMP_EXTRADATA_AT_BEGIN)*/){
+            int size= buf_size + avctx->extradata_size;
+            *poutbuf_size= size;
+            *poutbuf= av_malloc(size + FF_INPUT_BUFFER_PADDING_SIZE);
+
+            memcpy(*poutbuf, avctx->extradata, avctx->extradata_size);
+            memcpy((*poutbuf) + avctx->extradata_size, buf, buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
+            return 1;
+        }
+    }
+    return 0;
+}
+
+static int remove_extradata(AVBitStreamFilterContext *bsfc, AVCodecContext *avctx, const char *args,
+                     uint8_t **poutbuf, int *poutbuf_size,
+                     const uint8_t *buf, int buf_size, int keyframe){
+    int cmd= args ? *args : 0;
+    AVCodecParserContext *s;
+
+    if(!bsfc->parser){
+        bsfc->parser= av_parser_init(avctx->codec_id);
+    }
+    s= bsfc->parser;
+
+    if(s && s->parser->split){
+        if(  (((avctx->flags & CODEC_FLAG_GLOBAL_HEADER) || (avctx->flags2 & CODEC_FLAG2_LOCAL_HEADER)) && cmd=='a')
+           ||(!keyframe && cmd=='k')
+           ||(cmd=='e' || !cmd)
+          ){
+            int i= s->parser->split(avctx, buf, buf_size);
+            buf += i;
+            buf_size -= i;
+        }
+    }
+    *poutbuf= (uint8_t *) buf;
+    *poutbuf_size= buf_size;
+
+    return 0;
+}
+
+AVBitStreamFilter dump_extradata_bsf={
+    "dump_extra",
+    dump_extradata,
+};
+
+AVBitStreamFilter remove_extradata_bsf={
+    "remove_extra",
+    remove_extradata,
+};