1. ffmpeg
  2. Commit 6b55aab01a5c2e4c9f2851fdb9b7583f184b5241
Browse code

lavfi: create buffer reference in filters which need to access the ref later

Also add internal function ff_null_start_frame_keep_ref().

Fix crash when a following filter (e.g. settb) will unref the reference
passed by start_frame(), and then the reference is accessed in
end_frame() through inlink->cur_buf.

Stefano Sabatini authored on 2012/04/25 07:25:18
Showing 5 changed files
libavfilter/internal.h
History View file @ 6b55aab
... ... 
@@ -140,4 +140,13 @@ int ff_parse_channel_layout(int64_t *ret, const char *arg, void *log_ctx);
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  */
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 int ff_parse_packing_format(int *ret, const char *arg, void *log_ctx);
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+/**
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+ * Pass video frame along and keep an internal reference for later use.
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+ */
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+static inline void ff_null_start_frame_keep_ref(AVFilterLink *inlink,
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+                                                AVFilterBufferRef *picref)
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+{
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+    avfilter_start_frame(inlink->dst->outputs[0], avfilter_ref_buffer(picref, ~0));
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+}
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+
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 #endif /* AVFILTER_INTERNAL_H */
libavfilter/vf_bbox.c
History View file @ 6b55aab
... ... 
@@ -27,6 +27,7 @@
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 #include "libavutil/timestamp.h"
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 #include "avfilter.h"
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 #include "bbox.h"
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+#include "internal.h"
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 typedef struct {
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     unsigned int frame;
... ... 
@@ -85,6 +86,7 @@ static void end_frame(AVFilterLink *inlink)
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     av_log(ctx, AV_LOG_INFO, "\n");
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     bbox->frame++;
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+    avfilter_unref_buffer(picref);
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     avfilter_end_frame(inlink->dst->outputs[0]);
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 }
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... ... 
@@ -99,7 +101,7 @@ AVFilter avfilter_vf_bbox = {
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         { .name             = "default",
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           .type             = AVMEDIA_TYPE_VIDEO,
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           .get_video_buffer = avfilter_null_get_video_buffer,
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-          .start_frame      = avfilter_null_start_frame,
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+          .start_frame      = ff_null_start_frame_keep_ref,
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           .end_frame        = end_frame,
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           .min_perms        = AV_PERM_READ, },
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         { .name = NULL }
libavfilter/vf_blackdetect.c
History View file @ 6b55aab
... ... 
@@ -180,6 +180,7 @@ static void end_frame(AVFilterLink *inlink)
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     blackdetect->frame_count++;
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     blackdetect->nb_black_pixels = 0;
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+    avfilter_unref_buffer(picref);
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     avfilter_end_frame(inlink->dst->outputs[0]);
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 }
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... ... 
@@ -196,7 +197,7 @@ AVFilter avfilter_vf_blackdetect = {
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           .config_props     = config_input,
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           .draw_slice       = draw_slice,
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           .get_video_buffer = avfilter_null_get_video_buffer,
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-          .start_frame      = avfilter_null_start_frame,
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+          .start_frame      = ff_null_start_frame_keep_ref,
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           .end_frame        = end_frame, },
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         { .name = NULL }
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     },
libavfilter/vf_blackframe.c
History View file @ 6b55aab
... ... 
@@ -28,6 +28,7 @@
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  */
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 #include "avfilter.h"
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+#include "internal.h"
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 typedef struct {
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     unsigned int bamount; ///< black amount
... ... 
@@ -110,6 +111,7 @@ static void end_frame(AVFilterLink *inlink)
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     blackframe->frame++;
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     blackframe->nblack = 0;
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+    avfilter_unref_buffer(picref);
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     avfilter_end_frame(inlink->dst->outputs[0]);
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 }
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... ... 
@@ -126,7 +128,7 @@ AVFilter avfilter_vf_blackframe = {
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                                     .type             = AVMEDIA_TYPE_VIDEO,
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                                     .draw_slice       = draw_slice,
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                                     .get_video_buffer = avfilter_null_get_video_buffer,
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-                                    .start_frame      = avfilter_null_start_frame,
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+                                    .start_frame      = ff_null_start_frame_keep_ref,
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                                     .end_frame        = end_frame, },
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                                   { .name = NULL}},
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libavfilter/vf_showinfo.c
History View file @ 6b55aab
... ... 
@@ -27,6 +27,7 @@
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 #include "libavutil/pixdesc.h"
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 #include "libavutil/timestamp.h"
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 #include "avfilter.h"
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+#include "internal.h"
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 typedef struct {
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     unsigned int frame;
... ... 
@@ -79,6 +80,7 @@ static void end_frame(AVFilterLink *inlink)
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     av_log(ctx, AV_LOG_INFO, "]\n");
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     showinfo->frame++;
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+    avfilter_unref_buffer(picref);
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     avfilter_end_frame(inlink->dst->outputs[0]);
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 }
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... ... 
@@ -92,7 +94,7 @@ AVFilter avfilter_vf_showinfo = {
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     .inputs    = (const AVFilterPad[]) {{ .name       = "default",
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                                     .type             = AVMEDIA_TYPE_VIDEO,
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                                     .get_video_buffer = avfilter_null_get_video_buffer,
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-                                    .start_frame      = avfilter_null_start_frame,
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+                                    .start_frame      = ff_null_start_frame_keep_ref,
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                                     .end_frame        = end_frame,
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                                     .min_perms        = AV_PERM_READ, },
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                                   { .name = NULL}},