[FFmpeg-cvslog] pthread_frame: do not run hwaccel decoding asynchronously unless it's safe

Anton Khirnov git at videolan.org
Wed Apr 26 18:32:52 EEST 2017


ffmpeg | branch: master | Anton Khirnov <anton at khirnov.net> | Thu Nov 24 15:14:22 2016 +0100| [d4a91e65343be5d79a4afa61c791191e1b57499a] | committer: Anton Khirnov

pthread_frame: do not run hwaccel decoding asynchronously unless it's safe

Certain hardware decoding APIs are not guaranteed to be thread-safe, so
having the user access decoded hardware surfaces while the decoder is
running in another thread can cause failures (this is mainly known to
happen with DXVA2).

For such hwaccels, only allow the decoding thread to run while the user
is inside a lavc decode call (avcodec_send_packet/receive_frame).

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=d4a91e65343be5d79a4afa61c791191e1b57499a
---

 libavcodec/avcodec.h       |  5 +++++
 libavcodec/hwaccel.h       | 24 +++++++++++++++++++++
 libavcodec/pthread_frame.c | 52 ++++++++++++++++++++++++++++++++++++++++------
 libavcodec/vaapi_h264.c    |  2 ++
 libavcodec/vaapi_mpeg2.c   |  2 ++
 libavcodec/vaapi_mpeg4.c   |  3 +++
 libavcodec/vaapi_vc1.c     |  3 +++
 libavcodec/vaapi_vp8.c     |  2 ++
 libavcodec/vdpau_h264.c    |  2 ++
 libavcodec/vdpau_hevc.c    |  2 ++
 libavcodec/vdpau_mpeg12.c  |  3 +++
 libavcodec/vdpau_mpeg4.c   |  2 ++
 libavcodec/vdpau_vc1.c     |  3 +++
 libavcodec/version.h       |  2 +-
 14 files changed, 100 insertions(+), 7 deletions(-)

diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
index 0997141e2c..95da50b0e7 100644
--- a/libavcodec/avcodec.h
+++ b/libavcodec/avcodec.h
@@ -3375,6 +3375,11 @@ typedef struct AVHWAccel {
      * AVCodecInternal.hwaccel_priv_data.
      */
     int priv_data_size;
+
+    /**
+     * Internal hwaccel capabilities.
+     */
+    int caps_internal;
 } AVHWAccel;
 
 /**
diff --git a/libavcodec/hwaccel.h b/libavcodec/hwaccel.h
new file mode 100644
index 0000000000..60dbe81c8b
--- /dev/null
+++ b/libavcodec/hwaccel.h
@@ -0,0 +1,24 @@
+/*
+ * This file is part of Libav.
+ *
+ * Libav is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * Libav is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef AVCODEC_HWACCEL_H
+#define AVCODEC_HWACCEL_H
+
+#define HWACCEL_CAP_ASYNC_SAFE      (1 << 0)
+
+#endif /* AVCODEC_HWACCEL_H */
diff --git a/libavcodec/pthread_frame.c b/libavcodec/pthread_frame.c
index fd35456f59..f3a74c0bd8 100644
--- a/libavcodec/pthread_frame.c
+++ b/libavcodec/pthread_frame.c
@@ -34,6 +34,7 @@
 #endif
 
 #include "avcodec.h"
+#include "hwaccel.h"
 #include "internal.h"
 #include "pthread_internal.h"
 #include "thread.h"
@@ -101,6 +102,7 @@ typedef struct PerThreadContext {
     int die;                       ///< Set when the thread should exit.
 
     int hwaccel_serializing;
+    int async_serializing;
 } PerThreadContext;
 
 /**
@@ -116,6 +118,7 @@ typedef struct FrameThreadContext {
      * is used.
      */
     pthread_mutex_t hwaccel_mutex;
+    pthread_mutex_t async_mutex;
 
     int next_decoding;             ///< The next context to submit a packet to.
     int next_finished;             ///< The next context to return output from.
@@ -191,6 +194,11 @@ static attribute_align_arg void *frame_worker_thread(void *arg)
             pthread_mutex_unlock(&p->parent->hwaccel_mutex);
         }
 
+        if (p->async_serializing) {
+            p->async_serializing = 0;
+            pthread_mutex_unlock(&p->parent->async_mutex);
+        }
+
         atomic_store(&p->state, STATE_INPUT_READY);
 
         pthread_mutex_lock(&p->progress_mutex);
@@ -414,7 +422,11 @@ int ff_thread_decode_frame(AVCodecContext *avctx,
     FrameThreadContext *fctx = avctx->internal->thread_ctx;
     int finished = fctx->next_finished;
     PerThreadContext *p;
-    int err;
+    int err, ret;
+
+    /* release the async lock, permitting blocked hwaccel threads to
+     * go forward while we are in this function */
+    pthread_mutex_unlock(&fctx->async_mutex);
 
     /*
      * Submit a packet to the next decoding thread.
@@ -422,9 +434,11 @@ int ff_thread_decode_frame(AVCodecContext *avctx,
 
     p = &fctx->threads[fctx->next_decoding];
     err = update_context_from_user(p->avctx, avctx);
-    if (err) return err;
+    if (err)
+        goto finish;
     err = submit_packet(p, avpkt);
-    if (err) return err;
+    if (err)
+        goto finish;
 
     /*
      * If we're still receiving the initial packets, don't return a frame.
@@ -434,8 +448,10 @@ int ff_thread_decode_frame(AVCodecContext *avctx,
         if (fctx->next_decoding >= (avctx->thread_count-1)) fctx->delaying = 0;
 
         *got_picture_ptr=0;
-        if (avpkt->size)
-            return avpkt->size;
+        if (avpkt->size) {
+            ret = avpkt->size;
+            goto finish;
+        }
     }
 
     /*
@@ -477,7 +493,12 @@ int ff_thread_decode_frame(AVCodecContext *avctx,
     fctx->next_finished = finished;
 
     /* return the size of the consumed packet if no error occurred */
-    return (p->result >= 0) ? avpkt->size : p->result;
+    ret = (p->result >= 0) ? avpkt->size : p->result;
+finish:
+    pthread_mutex_lock(&fctx->async_mutex);
+    if (err < 0)
+        return err;
+    return ret;
 }
 
 void ff_thread_report_progress(ThreadFrame *f, int n, int field)
@@ -532,6 +553,13 @@ void ff_thread_finish_setup(AVCodecContext *avctx) {
         p->hwaccel_serializing = 1;
     }
 
+    /* this assumes that no hwaccel calls happen before ff_thread_finish_setup() */
+    if (avctx->hwaccel &&
+        !(avctx->hwaccel->caps_internal & HWACCEL_CAP_ASYNC_SAFE)) {
+        p->async_serializing = 1;
+        pthread_mutex_lock(&p->parent->async_mutex);
+    }
+
     pthread_mutex_lock(&p->progress_mutex);
 
     atomic_store(&p->state, STATE_SETUP_FINISHED);
@@ -545,6 +573,8 @@ static void park_frame_worker_threads(FrameThreadContext *fctx, int thread_count
 {
     int i;
 
+    pthread_mutex_unlock(&fctx->async_mutex);
+
     for (i = 0; i < thread_count; i++) {
         PerThreadContext *p = &fctx->threads[i];
 
@@ -555,6 +585,8 @@ static void park_frame_worker_threads(FrameThreadContext *fctx, int thread_count
             pthread_mutex_unlock(&p->progress_mutex);
         }
     }
+
+    pthread_mutex_lock(&fctx->async_mutex);
 }
 
 void ff_frame_thread_free(AVCodecContext *avctx, int thread_count)
@@ -613,6 +645,10 @@ void ff_frame_thread_free(AVCodecContext *avctx, int thread_count)
     av_freep(&fctx->threads);
     pthread_mutex_destroy(&fctx->buffer_mutex);
     pthread_mutex_destroy(&fctx->hwaccel_mutex);
+
+    pthread_mutex_unlock(&fctx->async_mutex);
+    pthread_mutex_destroy(&fctx->async_mutex);
+
     av_freep(&avctx->internal->thread_ctx);
 }
 
@@ -655,6 +691,10 @@ int ff_frame_thread_init(AVCodecContext *avctx)
 
     pthread_mutex_init(&fctx->buffer_mutex, NULL);
     pthread_mutex_init(&fctx->hwaccel_mutex, NULL);
+
+    pthread_mutex_init(&fctx->async_mutex, NULL);
+    pthread_mutex_lock(&fctx->async_mutex);
+
     fctx->delaying = 1;
 
     for (i = 0; i < thread_count; i++) {
diff --git a/libavcodec/vaapi_h264.c b/libavcodec/vaapi_h264.c
index 7d8dc34d63..f765523005 100644
--- a/libavcodec/vaapi_h264.c
+++ b/libavcodec/vaapi_h264.c
@@ -22,6 +22,7 @@
 
 #include "h264dec.h"
 #include "h264_ps.h"
+#include "hwaccel.h"
 #include "vaapi_decode.h"
 
 /**
@@ -399,4 +400,5 @@ AVHWAccel ff_h264_vaapi_hwaccel = {
     .init                 = &ff_vaapi_decode_init,
     .uninit               = &ff_vaapi_decode_uninit,
     .priv_data_size       = sizeof(VAAPIDecodeContext),
+    .caps_internal        = HWACCEL_CAP_ASYNC_SAFE,
 };
diff --git a/libavcodec/vaapi_mpeg2.c b/libavcodec/vaapi_mpeg2.c
index 6c10578b9d..a14d115fb0 100644
--- a/libavcodec/vaapi_mpeg2.c
+++ b/libavcodec/vaapi_mpeg2.c
@@ -20,6 +20,7 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
+#include "hwaccel.h"
 #include "mpegutils.h"
 #include "mpegvideo.h"
 #include "internal.h"
@@ -184,4 +185,5 @@ AVHWAccel ff_mpeg2_vaapi_hwaccel = {
     .init                 = &ff_vaapi_decode_init,
     .uninit               = &ff_vaapi_decode_uninit,
     .priv_data_size       = sizeof(VAAPIDecodeContext),
+    .caps_internal        = HWACCEL_CAP_ASYNC_SAFE,
 };
diff --git a/libavcodec/vaapi_mpeg4.c b/libavcodec/vaapi_mpeg4.c
index 4413cbfe34..b4819b804f 100644
--- a/libavcodec/vaapi_mpeg4.c
+++ b/libavcodec/vaapi_mpeg4.c
@@ -21,6 +21,7 @@
  */
 
 #include "h263.h"
+#include "hwaccel.h"
 #include "internal.h"
 #include "mpeg4video.h"
 #include "mpegvideo.h"
@@ -200,6 +201,7 @@ AVHWAccel ff_mpeg4_vaapi_hwaccel = {
     .init                 = &ff_vaapi_decode_init,
     .uninit               = &ff_vaapi_decode_uninit,
     .priv_data_size       = sizeof(VAAPIDecodeContext),
+    .caps_internal        = HWACCEL_CAP_ASYNC_SAFE,
 };
 #endif
 
@@ -216,5 +218,6 @@ AVHWAccel ff_h263_vaapi_hwaccel = {
     .init                 = &ff_vaapi_decode_init,
     .uninit               = &ff_vaapi_decode_uninit,
     .priv_data_size       = sizeof(VAAPIDecodeContext),
+    .caps_internal        = HWACCEL_CAP_ASYNC_SAFE,
 };
 #endif
diff --git a/libavcodec/vaapi_vc1.c b/libavcodec/vaapi_vc1.c
index fe1a20fcbb..42634f2baf 100644
--- a/libavcodec/vaapi_vc1.c
+++ b/libavcodec/vaapi_vc1.c
@@ -20,6 +20,7 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
+#include "hwaccel.h"
 #include "internal.h"
 #include "vaapi_decode.h"
 #include "vc1.h"
@@ -399,6 +400,7 @@ AVHWAccel ff_wmv3_vaapi_hwaccel = {
     .init                 = &ff_vaapi_decode_init,
     .uninit               = &ff_vaapi_decode_uninit,
     .priv_data_size       = sizeof(VAAPIDecodeContext),
+    .caps_internal        = HWACCEL_CAP_ASYNC_SAFE,
 };
 #endif
 
@@ -414,4 +416,5 @@ AVHWAccel ff_vc1_vaapi_hwaccel = {
     .init                 = &ff_vaapi_decode_init,
     .uninit               = &ff_vaapi_decode_uninit,
     .priv_data_size       = sizeof(VAAPIDecodeContext),
+    .caps_internal        = HWACCEL_CAP_ASYNC_SAFE,
 };
diff --git a/libavcodec/vaapi_vp8.c b/libavcodec/vaapi_vp8.c
index 70e9cec3d4..1ba5c7ec94 100644
--- a/libavcodec/vaapi_vp8.c
+++ b/libavcodec/vaapi_vp8.c
@@ -19,6 +19,7 @@
 #include <va/va.h>
 #include <va/va_dec_vp8.h>
 
+#include "hwaccel.h"
 #include "vaapi_decode.h"
 #include "vp8.h"
 
@@ -231,4 +232,5 @@ AVHWAccel ff_vp8_vaapi_hwaccel = {
     .init                 = &ff_vaapi_decode_init,
     .uninit               = &ff_vaapi_decode_uninit,
     .priv_data_size       = sizeof(VAAPIDecodeContext),
+    .caps_internal        = HWACCEL_CAP_ASYNC_SAFE,
 };
diff --git a/libavcodec/vdpau_h264.c b/libavcodec/vdpau_h264.c
index 3e13b76160..a18941848a 100644
--- a/libavcodec/vdpau_h264.c
+++ b/libavcodec/vdpau_h264.c
@@ -27,6 +27,7 @@
 #include "internal.h"
 #include "h264dec.h"
 #include "h264_ps.h"
+#include "hwaccel.h"
 #include "mpegutils.h"
 #include "vdpau.h"
 #include "vdpau_internal.h"
@@ -273,4 +274,5 @@ AVHWAccel ff_h264_vdpau_hwaccel = {
     .init           = vdpau_h264_init,
     .uninit         = ff_vdpau_common_uninit,
     .priv_data_size = sizeof(VDPAUContext),
+    .caps_internal  = HWACCEL_CAP_ASYNC_SAFE,
 };
diff --git a/libavcodec/vdpau_hevc.c b/libavcodec/vdpau_hevc.c
index 829945614c..399253e297 100644
--- a/libavcodec/vdpau_hevc.c
+++ b/libavcodec/vdpau_hevc.c
@@ -26,6 +26,7 @@
 #include "internal.h"
 #include "hevc_data.h"
 #include "hevcdec.h"
+#include "hwaccel.h"
 #include "vdpau.h"
 #include "vdpau_internal.h"
 
@@ -424,4 +425,5 @@ AVHWAccel ff_hevc_vdpau_hwaccel = {
     .init           = vdpau_hevc_init,
     .uninit         = ff_vdpau_common_uninit,
     .priv_data_size = sizeof(VDPAUContext),
+    .caps_internal  = HWACCEL_CAP_ASYNC_SAFE,
 };
diff --git a/libavcodec/vdpau_mpeg12.c b/libavcodec/vdpau_mpeg12.c
index cb6f81a76d..2af3201e95 100644
--- a/libavcodec/vdpau_mpeg12.c
+++ b/libavcodec/vdpau_mpeg12.c
@@ -24,6 +24,7 @@
 #include <vdpau/vdpau.h>
 
 #include "avcodec.h"
+#include "hwaccel.h"
 #include "mpegvideo.h"
 #include "vdpau.h"
 #include "vdpau_internal.h"
@@ -114,6 +115,7 @@ AVHWAccel ff_mpeg1_vdpau_hwaccel = {
     .init           = vdpau_mpeg1_init,
     .uninit         = ff_vdpau_common_uninit,
     .priv_data_size = sizeof(VDPAUContext),
+    .caps_internal  = HWACCEL_CAP_ASYNC_SAFE,
 };
 #endif
 
@@ -148,5 +150,6 @@ AVHWAccel ff_mpeg2_vdpau_hwaccel = {
     .init           = vdpau_mpeg2_init,
     .uninit         = ff_vdpau_common_uninit,
     .priv_data_size = sizeof(VDPAUContext),
+    .caps_internal  = HWACCEL_CAP_ASYNC_SAFE,
 };
 #endif
diff --git a/libavcodec/vdpau_mpeg4.c b/libavcodec/vdpau_mpeg4.c
index fcad42f0a4..4f3d6e5448 100644
--- a/libavcodec/vdpau_mpeg4.c
+++ b/libavcodec/vdpau_mpeg4.c
@@ -24,6 +24,7 @@
 #include <vdpau/vdpau.h>
 
 #include "avcodec.h"
+#include "hwaccel.h"
 #include "mpeg4video.h"
 #include "vdpau.h"
 #include "vdpau_internal.h"
@@ -118,4 +119,5 @@ AVHWAccel ff_mpeg4_vdpau_hwaccel = {
     .init           = vdpau_mpeg4_init,
     .uninit         = ff_vdpau_common_uninit,
     .priv_data_size = sizeof(VDPAUContext),
+    .caps_internal  = HWACCEL_CAP_ASYNC_SAFE,
 };
diff --git a/libavcodec/vdpau_vc1.c b/libavcodec/vdpau_vc1.c
index 4f87c52ecc..251d1aae5d 100644
--- a/libavcodec/vdpau_vc1.c
+++ b/libavcodec/vdpau_vc1.c
@@ -24,6 +24,7 @@
 #include <vdpau/vdpau.h>
 
 #include "avcodec.h"
+#include "hwaccel.h"
 #include "vc1.h"
 #include "vdpau.h"
 #include "vdpau_internal.h"
@@ -143,6 +144,7 @@ AVHWAccel ff_wmv3_vdpau_hwaccel = {
     .init           = vdpau_vc1_init,
     .uninit         = ff_vdpau_common_uninit,
     .priv_data_size = sizeof(VDPAUContext),
+    .caps_internal  = HWACCEL_CAP_ASYNC_SAFE,
 };
 #endif
 
@@ -158,4 +160,5 @@ AVHWAccel ff_vc1_vdpau_hwaccel = {
     .init           = vdpau_vc1_init,
     .uninit         = ff_vdpau_common_uninit,
     .priv_data_size = sizeof(VDPAUContext),
+    .caps_internal  = HWACCEL_CAP_ASYNC_SAFE,
 };
diff --git a/libavcodec/version.h b/libavcodec/version.h
index adab9b47a3..3756275086 100644
--- a/libavcodec/version.h
+++ b/libavcodec/version.h
@@ -29,7 +29,7 @@
 
 #define LIBAVCODEC_VERSION_MAJOR 57
 #define LIBAVCODEC_VERSION_MINOR 30
-#define LIBAVCODEC_VERSION_MICRO  0
+#define LIBAVCODEC_VERSION_MICRO  1
 
 #define LIBAVCODEC_VERSION_INT  AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \
                                                LIBAVCODEC_VERSION_MINOR, \



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