[FFmpeg-devel] [PATCH v2 5/6] avcodec/hevc/sei: dynamically allocate 3D Reference Displays Information SEI messages

[James Almer <jamrial@gmail.com>]

Considerably reduces the size of HEVCSEI.

Signed-off-by: James Almer <jamrial@gmail.com>
---
Fixed segfaults.

 libavcodec/hevc/hevcdec.c | 10 +++++-----
 libavcodec/hevc/refs.c    |  4 ++--
 libavcodec/hevc/sei.c     |  6 +++++-
 libavcodec/hevc/sei.h     |  6 +++++-
 4 files changed, 17 insertions(+), 9 deletions(-)

diff --git a/libavcodec/hevc/hevcdec.c b/libavcodec/hevc/hevcdec.c
index e9c045f7a1..881538fb91 100644
--- a/libavcodec/hevc/hevcdec.c
+++ b/libavcodec/hevc/hevcdec.c
@@ -429,7 +429,7 @@ FF_ENABLE_DEPRECATION_WARNINGS
 
 static int export_multilayer(HEVCContext *s, const HEVCVPS *vps)
 {
-    const HEVCSEITDRDI *tdrdi = &s->sei.tdrdi;
+    const HEVCSEITDRDI *tdrdi = s->sei.tdrdi;
 
     av_freep(&s->view_ids_available);
     s->nb_view_ids_available = 0;
@@ -444,7 +444,7 @@ static int export_multilayer(HEVCContext *s, const HEVCVPS *vps)
     if (!s->view_ids_available)
         return AVERROR(ENOMEM);
 
-    if (tdrdi->num_ref_displays) {
+    if (tdrdi && tdrdi->num_ref_displays) {
         s->view_pos_available = av_calloc(vps->nb_layers, sizeof(*s->view_pos_available));
         if (!s->view_pos_available)
             return AVERROR(ENOMEM);
@@ -454,9 +454,9 @@ static int export_multilayer(HEVCContext *s, const HEVCVPS *vps)
         s->view_ids_available[i] = vps->view_id[i];
 
         if (s->view_pos_available) {
-            s->view_pos_available[i] = vps->view_id[i] == tdrdi->left_view_id[0]  ?
+            s->view_pos_available[i] = tdrdi && (vps->view_id[i] == tdrdi->left_view_id[0])  ?
                                        AV_STEREO3D_VIEW_LEFT                      :
-                                       vps->view_id[i] == tdrdi->right_view_id[0] ?
+                                       tdrdi && (vps->view_id[i] == tdrdi->right_view_id[0]) ?
                                        AV_STEREO3D_VIEW_RIGHT : AV_STEREO3D_VIEW_UNSPEC;
         }
     }
@@ -4015,7 +4015,7 @@ static int hevc_update_thread_context(AVCodecContext *dst,
     s->sei.common.frame_packing        = s0->sei.common.frame_packing;
     s->sei.common.display_orientation  = s0->sei.common.display_orientation;
     s->sei.common.alternative_transfer = s0->sei.common.alternative_transfer;
-    s->sei.tdrdi                       = s0->sei.tdrdi;
+    av_refstruct_replace(&s->sei.tdrdi, s0->sei.tdrdi);
 
     return 0;
 }
diff --git a/libavcodec/hevc/refs.c b/libavcodec/hevc/refs.c
index dd7f7f95a8..d1d2f27a9b 100644
--- a/libavcodec/hevc/refs.c
+++ b/libavcodec/hevc/refs.c
@@ -104,7 +104,7 @@ static HEVCFrame *alloc_frame(HEVCContext *s, HEVCLayerContext *l)
 
         // add view ID side data if it's nontrivial
         if (vps->nb_layers > 1 || view_id) {
-            HEVCSEITDRDI *tdrdi = &s->sei.tdrdi;
+            HEVCSEITDRDI *tdrdi = s->sei.tdrdi;
             AVFrameSideData *sd = av_frame_side_data_new(&frame->f->side_data,
                                                          &frame->f->nb_side_data,
                                                          AV_FRAME_DATA_VIEW_ID,
@@ -113,7 +113,7 @@ static HEVCFrame *alloc_frame(HEVCContext *s, HEVCLayerContext *l)
                 goto fail;
             *(int*)sd->data = view_id;
 
-            if (tdrdi->num_ref_displays) {
+            if (tdrdi && tdrdi->num_ref_displays) {
                 AVStereo3D *stereo_3d;
 
                 stereo_3d = av_stereo3d_create_side_data(frame->f);
diff --git a/libavcodec/hevc/sei.c b/libavcodec/hevc/sei.c
index 8793d86fdc..588516043b 100644
--- a/libavcodec/hevc/sei.c
+++ b/libavcodec/hevc/sei.c
@@ -220,7 +220,11 @@ static int decode_nal_sei_prefix(GetBitContext *gb, GetByteContext *gbyte,
     case SEI_TYPE_TIME_CODE:
         return decode_nal_sei_timecode(&s->timecode, gb);
     case SEI_TYPE_THREE_DIMENSIONAL_REFERENCE_DISPLAYS_INFO:
-        return decode_nal_sei_3d_reference_displays_info(&s->tdrdi, gb);
+        av_refstruct_unref(&s->tdrdi);
+        s->tdrdi = av_refstruct_allocz(sizeof(*s->tdrdi));
+        if (!s->tdrdi)
+            return AVERROR(ENOMEM);
+        return decode_nal_sei_3d_reference_displays_info(s->tdrdi, gb);
     default: {
         int ret = ff_h2645_sei_message_decode(&s->common, type, AV_CODEC_ID_HEVC,
                                               gb, gbyte, logctx);
diff --git a/libavcodec/hevc/sei.h b/libavcodec/hevc/sei.h
index ee640003bc..42ee6a20b7 100644
--- a/libavcodec/hevc/sei.h
+++ b/libavcodec/hevc/sei.h
@@ -24,6 +24,7 @@
 #include <stdint.h>
 
 #include "libavutil/buffer.h"
+#include "libavutil/refstruct.h"
 
 #include "libavcodec/get_bits.h"
 #include "libavcodec/h2645_sei.h"
@@ -101,7 +102,9 @@ typedef struct HEVCSEI {
     HEVCSEIPictureTiming picture_timing;
     int active_seq_parameter_set_id;
     HEVCSEITimeCode timecode;
-    HEVCSEITDRDI tdrdi;
+
+    // Dynamic allocations due to large size.
+    HEVCSEITDRDI *tdrdi;
 } HEVCSEI;
 
 struct HEVCParamSets;
@@ -118,6 +121,7 @@ int ff_hevc_decode_nal_sei(GetBitContext *gb, void *logctx, HEVCSEI *s,
  */
 static inline void ff_hevc_reset_sei(HEVCSEI *sei)
 {
+    av_refstruct_unref(&sei->tdrdi);
     ff_h2645_sei_reset(&sei->common);
 }
 
-- 
2.48.1

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