From bb463d81020a2f3c5cf3403e18f980171773f48a Mon Sep 17 00:00:00 2001
From: Michael Niedermayer <michaelni@gmx.at>
Date: Sun, 27 Apr 2003 01:11:26 +0000
Subject: [PATCH] 10l (returning negative number of consumed bytes if the first
startcode of a frame was split between 2 buffers)
Originally committed as revision 1824 to svn://svn.ffmpeg.org/ffmpeg/trunk
---
libavcodec/mpeg12.c | 8 +++-----
libavcodec/mpegvideo.c | 35 ++++++++++++++++++++++++++++++++---
libavcodec/mpegvideo.h | 5 ++++-
3 files changed, 39 insertions(+), 9 deletions(-)
diff --git a/libavcodec/mpeg12.c b/libavcodec/mpeg12.c
index d16eaa1da6c..d3cef315e4a 100644
--- a/libavcodec/mpeg12.c
+++ b/libavcodec/mpeg12.c
@@ -2190,7 +2190,7 @@ static int mpeg1_find_frame_end(MpegEncContext *s, uint8_t *buf, int buf_size){
}
}
pc->state= state;
- return -1;
+ return END_NOT_FOUND;
}
/* handle buffering and image synchronisation */
@@ -2218,9 +2218,7 @@ static int mpeg_decode_frame(AVCodecContext *avctx,
}
if(s2->flags&CODEC_FLAG_TRUNCATED){
- int next;
-
- next= mpeg1_find_frame_end(s2, buf, buf_size);
+ int next= mpeg1_find_frame_end(s2, buf, buf_size);
if( ff_combine_frame(s2, next, &buf, &buf_size) < 0 )
return buf_size;
@@ -2288,7 +2286,7 @@ static int mpeg_decode_frame(AVCodecContext *avctx,
if (ret == DECODE_SLICE_EOP) {
if(s2->last_picture_ptr) //FIXME merge with the stuff in mpeg_decode_slice
*data_size = sizeof(AVPicture);
- return FFMAX(1, buf_ptr - buf - s2->parse_context.last_index);
+ return FFMAX(0, buf_ptr - buf - s2->parse_context.last_index);
}else if(ret < 0){
if(ret == DECODE_SLICE_ERROR)
ff_er_add_slice(s2, s2->resync_mb_x, s2->resync_mb_y, s2->mb_x, s2->mb_y, AC_ERROR|DC_ERROR|MV_ERROR);
diff --git a/libavcodec/mpegvideo.c b/libavcodec/mpegvideo.c
index 2ec42aea399..b63a011246b 100644
--- a/libavcodec/mpegvideo.c
+++ b/libavcodec/mpegvideo.c
@@ -2770,17 +2770,33 @@ static void encode_mb(MpegEncContext *s, int motion_x, int motion_y)
*/
int ff_combine_frame( MpegEncContext *s, int next, uint8_t **buf, int *buf_size){
ParseContext *pc= &s->parse_context;
-
+
+#if 0
+ if(pc->overread){
+ printf("overread %d, state:%X next:%d index:%d o_index:%d\n", pc->overread, pc->state, next, pc->index, pc->overread_index);
+ printf("%X %X %X %X\n", (*buf)[0], (*buf)[1],(*buf)[2],(*buf)[3]);
+ }
+#endif
+
+ /* copy overreaded byes from last frame into buffer */
+ for(; pc->overread>0; pc->overread--){
+ pc->buffer[pc->index++]= pc->buffer[pc->overread_index++];
+ }
+
pc->last_index= pc->index;
- if(next==-1){
+ /* copy into buffer end return */
+ if(next == END_NOT_FOUND){
pc->buffer= av_fast_realloc(pc->buffer, &pc->buffer_size, (*buf_size) + pc->index + FF_INPUT_BUFFER_PADDING_SIZE);
memcpy(&pc->buffer[pc->index], *buf, *buf_size);
pc->index += *buf_size;
return -1;
}
-
+
+ pc->overread_index= pc->index + next;
+
+ /* append to buffer */
if(pc->index){
pc->buffer= av_fast_realloc(pc->buffer, &pc->buffer_size, next + pc->index + FF_INPUT_BUFFER_PADDING_SIZE);
@@ -2790,6 +2806,19 @@ int ff_combine_frame( MpegEncContext *s, int next, uint8_t **buf, int *buf_size)
*buf_size= pc->last_index + next;
}
+ /* store overread bytes */
+ for(;next < 0; next++){
+ pc->state = (pc->state<<8) | pc->buffer[pc->last_index + next];
+ pc->overread++;
+ }
+
+#if 0
+ if(pc->overread){
+ printf("overread %d, state:%X next:%d index:%d o_index:%d\n", pc->overread, pc->state, next, pc->index, pc->overread_index);
+ printf("%X %X %X %X\n", (*buf)[0], (*buf)[1],(*buf)[2],(*buf)[3]);
+ }
+#endif
+
return 0;
}
diff --git a/libavcodec/mpegvideo.h b/libavcodec/mpegvideo.h
index dc15a51f89f..2cbc0ef1929 100644
--- a/libavcodec/mpegvideo.h
+++ b/libavcodec/mpegvideo.h
@@ -205,8 +205,10 @@ typedef struct ParseContext{
int index;
int last_index;
int buffer_size;
- int state;
+ uint32_t state; ///< contains the last few bytes in MSB order
int frame_start_found;
+ int overread; ///< the number of bytes which where irreversibly read from the next frame
+ int overread_index; ///< the index into ParseContext.buffer of the overreaded bytes
} ParseContext;
struct MpegEncContext;
@@ -709,6 +711,7 @@ void ff_draw_horiz_band(MpegEncContext *s, int y, int h);
void ff_emulated_edge_mc(MpegEncContext *s, uint8_t *src, int linesize, int block_w, int block_h,
int src_x, int src_y, int w, int h);
char ff_get_pict_type_char(int pict_type);
+#define END_NOT_FOUND -100
int ff_combine_frame( MpegEncContext *s, int next, uint8_t **buf, int *buf_size);
void ff_print_debug_info(MpegEncContext *s, Picture *pict);
--
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