From 549d0bdca53af7a6e0c612ab4b03baecf3a5878f Mon Sep 17 00:00:00 2001
From: Anton Khirnov <anton@khirnov.net>
Date: Wed, 26 Oct 2016 13:41:12 +0200
Subject: [PATCH] decode: be more explicit about storing the last packet
properties
The current code stores a pointer to the packet passed to the decoder,
which is then used during get_buffer() for timestamps and side data
passthrough. However, since this is a pointer to user data which we do
not own, storing it is potentially dangerous. It is also ill defined for
the new decoding API with split input/output.
Fix this problem by making an explicit internally owned copy of the
packet properties.
---
libavcodec/decode.c | 33 ++++++++++++++++++++-------------
libavcodec/internal.h | 6 +++---
libavcodec/pthread_frame.c | 2 +-
libavcodec/utils.c | 8 ++++++++
4 files changed, 32 insertions(+), 17 deletions(-)
diff --git a/libavcodec/decode.c b/libavcodec/decode.c
index 00085c3b4dc..b02278d3a68 100644
--- a/libavcodec/decode.c
+++ b/libavcodec/decode.c
@@ -99,6 +99,14 @@ fail2:
return 0;
}
+static int extract_packet_props(AVCodecInternal *avci, const AVPacket *pkt)
+{
+ av_packet_unref(avci->last_pkt_props);
+ if (pkt)
+ return av_packet_copy_props(avci->last_pkt_props, pkt);
+ return 0;
+}
+
static int unrefcount_frame(AVCodecInternal *avci, AVFrame *frame)
{
int ret;
@@ -304,7 +312,10 @@ int attribute_align_arg avcodec_decode_video2(AVCodecContext *avctx, AVFrame *pi
return AVERROR(ENOSYS);
}
- avctx->internal->pkt = avpkt;
+ ret = extract_packet_props(avci, avpkt);
+ if (ret < 0)
+ return ret;
+
ret = apply_param_change(avctx, avpkt);
if (ret < 0)
return ret;
@@ -368,7 +379,9 @@ int attribute_align_arg avcodec_decode_audio4(AVCodecContext *avctx,
return AVERROR(ENOSYS);
}
- avctx->internal->pkt = avpkt;
+ ret = extract_packet_props(avci, avpkt);
+ if (ret < 0)
+ return ret;
if (!avpkt->data && avpkt->size) {
av_log(avctx, AV_LOG_ERROR, "invalid packet: NULL data, size != 0\n");
@@ -408,7 +421,10 @@ int avcodec_decode_subtitle2(AVCodecContext *avctx, AVSubtitle *sub,
{
int ret;
- avctx->internal->pkt = avpkt;
+ ret = extract_packet_props(avctx->internal, avpkt);
+ if (ret < 0)
+ return ret;
+
*got_sub_ptr = 0;
ret = avctx->codec->decode(avctx, sub, got_sub_ptr, avpkt);
if (*got_sub_ptr)
@@ -739,7 +755,7 @@ int avcodec_default_get_buffer2(AVCodecContext *avctx, AVFrame *frame, int flags
int ff_decode_frame_props(AVCodecContext *avctx, AVFrame *frame)
{
- AVPacket *pkt = avctx->internal->pkt;
+ AVPacket *pkt = avctx->internal->last_pkt_props;
int i;
struct {
enum AVPacketSideDataType packet;
@@ -759,15 +775,6 @@ int ff_decode_frame_props(AVCodecContext *avctx, AVFrame *frame)
frame->chroma_location = avctx->chroma_sample_location;
frame->reordered_opaque = avctx->reordered_opaque;
- if (!pkt) {
-#if FF_API_PKT_PTS
-FF_DISABLE_DEPRECATION_WARNINGS
- frame->pkt_pts = AV_NOPTS_VALUE;
-FF_ENABLE_DEPRECATION_WARNINGS
-#endif
- frame->pts = AV_NOPTS_VALUE;
- return 0;
- }
#if FF_API_PKT_PTS
FF_DISABLE_DEPRECATION_WARNINGS
diff --git a/libavcodec/internal.h b/libavcodec/internal.h
index 4bde09ab8ad..2ca7a45e811 100644
--- a/libavcodec/internal.h
+++ b/libavcodec/internal.h
@@ -131,10 +131,10 @@ typedef struct AVCodecInternal {
void *thread_ctx;
/**
- * Current packet as passed into the decoder, to avoid having to pass the
- * packet into every function.
+ * Properties (timestamps+side data) extracted from the last packet passed
+ * for decoding.
*/
- AVPacket *pkt;
+ AVPacket *last_pkt_props;
/**
* hwaccel-specific private data
diff --git a/libavcodec/pthread_frame.c b/libavcodec/pthread_frame.c
index 2736a81efea..75f4ff46247 100644
--- a/libavcodec/pthread_frame.c
+++ b/libavcodec/pthread_frame.c
@@ -656,7 +656,7 @@ int ff_frame_thread_init(AVCodecContext *avctx)
}
*copy->internal = *src->internal;
copy->internal->thread_ctx = p;
- copy->internal->pkt = &p->avpkt;
+ copy->internal->last_pkt_props = &p->avpkt;
if (!i) {
src = copy;
diff --git a/libavcodec/utils.c b/libavcodec/utils.c
index 5350eb819a9..b569b48f7a8 100644
--- a/libavcodec/utils.c
+++ b/libavcodec/utils.c
@@ -433,6 +433,12 @@ int attribute_align_arg avcodec_open2(AVCodecContext *avctx, const AVCodec *code
goto free_and_end;
}
+ avctx->internal->last_pkt_props = av_packet_alloc();
+ if (!avctx->internal->last_pkt_props) {
+ ret = AVERROR(ENOMEM);
+ goto free_and_end;
+ }
+
if (codec->priv_data_size > 0) {
if (!avctx->priv_data) {
avctx->priv_data = av_mallocz(codec->priv_data_size);
@@ -713,6 +719,7 @@ FF_ENABLE_DEPRECATION_WARNINGS
av_frame_free(&avctx->internal->to_free);
av_frame_free(&avctx->internal->buffer_frame);
av_packet_free(&avctx->internal->buffer_pkt);
+ av_packet_free(&avctx->internal->last_pkt_props);
av_freep(&avctx->internal->pool);
}
av_freep(&avctx->internal);
@@ -753,6 +760,7 @@ av_cold int avcodec_close(AVCodecContext *avctx)
av_frame_free(&avctx->internal->to_free);
av_frame_free(&avctx->internal->buffer_frame);
av_packet_free(&avctx->internal->buffer_pkt);
+ av_packet_free(&avctx->internal->last_pkt_props);
for (i = 0; i < FF_ARRAY_ELEMS(pool->pools); i++)
av_buffer_pool_uninit(&pool->pools[i]);
av_freep(&avctx->internal->pool);
--
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