[FFmpeg-devel] [PATCH 08/12] lavc/frame_thread_encoder: avoid assigning a whole AVCodecContext

[Anton Khirnov]

It is highly unsafe, as AVCodecContext contains many allocated fields.
Copying information via AVCodecParameters and with av_opt_copy() should
handle everything needed by thread workers.
---
 libavcodec/frame_thread_encoder.c | 26 ++++++++++++++++++++------
 1 file changed, 20 insertions(+), 6 deletions(-)

diff --git a/libavcodec/frame_thread_encoder.c b/libavcodec/frame_thread_encoder.c
index cda5158117..744062b776 100644
--- a/libavcodec/frame_thread_encoder.c
+++ b/libavcodec/frame_thread_encoder.c
@@ -28,6 +28,7 @@
 #include "libavutil/thread.h"
 #include "avcodec.h"
 #include "avcodec_internal.h"
+#include "codec_par.h"
 #include "encode.h"
 #include "internal.h"
 #include "pthread_internal.h"
@@ -121,6 +122,7 @@ av_cold int ff_frame_thread_encoder_init(AVCodecContext *avctx)
     int i=0;
     ThreadContext *c;
     AVCodecContext *thread_avctx = NULL;
+    AVCodecParameters *par = NULL;
     int ret;
 
     if(   !(avctx->thread_type & FF_THREAD_FRAME)
@@ -194,18 +196,27 @@ av_cold int ff_frame_thread_encoder_init(AVCodecContext *avctx)
         }
     }
 
+    par = avcodec_parameters_alloc();
+    if (!par) {
+        ret = AVERROR(ENOMEM);
+        goto fail;
+    }
+
+    ret = avcodec_parameters_from_context(par, avctx);
+    if (ret < 0)
+        goto fail;
+
     for(i=0; i<avctx->thread_count ; i++){
-        void *tmpv;
         thread_avctx = avcodec_alloc_context3(avctx->codec);
         if (!thread_avctx) {
             ret = AVERROR(ENOMEM);
             goto fail;
         }
-        tmpv = thread_avctx->priv_data;
-        *thread_avctx = *avctx;
-        thread_avctx->priv_data = tmpv;
-        thread_avctx->internal = NULL;
-        thread_avctx->hw_frames_ctx = NULL;
+
+        ret = avcodec_parameters_to_context(thread_avctx, par);
+        if (ret < 0)
+            goto fail;
+
         ret = av_opt_copy(thread_avctx, avctx);
         if (ret < 0)
             goto fail;
@@ -227,10 +238,13 @@ av_cold int ff_frame_thread_encoder_init(AVCodecContext *avctx)
         }
     }
 
+    avcodec_parameters_free(&par);
+
     avctx->active_thread_type = FF_THREAD_FRAME;
 
     return 0;
 fail:
+    avcodec_parameters_free(&par);
     ff_codec_close(thread_avctx);
     av_freep(&thread_avctx);
     avctx->thread_count = i;
-- 
2.43.0