8 Jul 2021, 21:20 by andreas.rheinha...@outlook.com:
> Lynne:
>
>> Apr 26, 2021, 03:27 by andreas.rheinha...@outlook.com:
>>
>>> Lynne:
>>>
>>>> From 097aed2ac33dda0bb2052d8b0402711ce95079ba Mon Sep 17 00:00:00 2001
>>>> From: Lynne <d...@lynne.ee>
>>>> Date: Sat, 23 Jan 2021 19:56:18 +0100
>>>> Subject: [PATCH] avpacket: ABI bump additions
>>>>
>>>> ---
>>>> libavcodec/avpacket.c | 5 +++++
>>>> libavcodec/packet.h | 21 +++++++++++++++++++++
>>>> 2 files changed, 26 insertions(+)
>>>>
>>>> diff --git a/libavcodec/avpacket.c b/libavcodec/avpacket.c
>>>> index e32c467586..03b73b3b53 100644
>>>> --- a/libavcodec/avpacket.c
>>>> +++ b/libavcodec/avpacket.c
>>>> @@ -382,6 +382,10 @@ int av_packet_copy_props(AVPacket *dst, const
>>>> AVPacket *src)
>>>> dst->flags = src->flags;
>>>> dst->stream_index = src->stream_index;
>>>>
>>>> + i = av_buffer_replace(&dst->opaque_ref, src->opaque_ref);
>>>> + if (i < 0)
>>>> + return i;
>>>>
>>>
>>> 1. Don't use i here; add a new variable.
>>> 2. Up until now, av_packet_ref() and av_packet_copy_props() treat the
>>> destination packet as uninitialized and make no attempt at unreferencing
>>> its content; yet you try to reuse opaque_ref. Even worse, you might
>>> return potentially dangerous packets: If the properties were
>>> uninitialized and av_packet_copy_props() failed, then the caller were
>>> not allowed to unreference the packet even when the non-properties were
>>> set to sane values. The easiest way to fix this is to move setting
>>> opaque ref to the place after initializing side_data below and either
>>> set dst->opaque_ref to NULL before av_buffer_replace() or to not use
>>> av_buffer_replace(). It may also be best to unref it again if copying
>>> side data fails.
>>>
>>>> +
>>>> dst->side_data = NULL;
>>>> dst->side_data_elems = 0;
>>>> for (i = 0; i < src->side_data_elems; i++) {
>>>> @@ -403,6 +407,7 @@ int av_packet_copy_props(AVPacket *dst, const AVPacket
>>>> *src)
>>>> void av_packet_unref(AVPacket *pkt)
>>>> {
>>>> av_packet_free_side_data(pkt);
>>>> + av_buffer_unref(&pkt->opaque_ref);
>>>> av_buffer_unref(&pkt->buf);
>>>> get_packet_defaults(pkt);
>>>> }
>>>> diff --git a/libavcodec/packet.h b/libavcodec/packet.h
>>>> index fad8341c12..c29ad18a2b 100644
>>>> --- a/libavcodec/packet.h
>>>> +++ b/libavcodec/packet.h
>>>> @@ -383,6 +383,27 @@ typedef struct AVPacket {
>>>> int64_t duration;
>>>>
>>>> int64_t pos; ///< byte position in stream, -1
>>>> if unknown
>>>> +
>>>> + /**
>>>> + * for some private data of the user
>>>> + */
>>>> + void *opaque;
>>>>
>>>
>>> The corresponding AVFrame field is copied when copying props.
>>>
>>
>> Fixed both, thanks. Also copied the time_base field and made av_init_packet()
>> initialize all fields.
>>
>
> Your new version is still not correct: If copying side data fails, the
> function returns without initializing opaque_ref at all, thereby making
> it dangerous to unref the packet (which e.g. av_packet_ref() does).
>
> - Andreas
>
Fixed, and made sure to unref it if copying side data fails.
>From 2b252692ead788faf81b104ebda041ff18a06191 Mon Sep 17 00:00:00 2001
From: Lynne <d...@lynne.ee>
Date: Sat, 23 Jan 2021 19:56:18 +0100
Subject: [PATCH v2] avpacket: ABI bump additions
---
libavcodec/avpacket.c | 17 +++++++++++++++--
libavcodec/packet.h | 21 +++++++++++++++++++++
2 files changed, 36 insertions(+), 2 deletions(-)
diff --git a/libavcodec/avpacket.c b/libavcodec/avpacket.c
index 800bee3489..075b219475 100644
--- a/libavcodec/avpacket.c
+++ b/libavcodec/avpacket.c
@@ -26,6 +26,7 @@
#include "libavutil/internal.h"
#include "libavutil/mathematics.h"
#include "libavutil/mem.h"
+#include "libavutil/rational.h"
#include "bytestream.h"
#include "internal.h"
@@ -44,6 +45,9 @@ void av_init_packet(AVPacket *pkt)
pkt->buf = NULL;
pkt->side_data = NULL;
pkt->side_data_elems = 0;
+ pkt->opaque = NULL;
+ pkt->opaque_ref = NULL;
+ pkt->time_base = av_make_q(0, 0);
}
#endif
@@ -374,7 +378,7 @@ int av_packet_shrink_side_data(AVPacket *pkt, enum AVPacketSideDataType type,
int av_packet_copy_props(AVPacket *dst, const AVPacket *src)
{
- int i;
+ int i, ret;
dst->pts = src->pts;
dst->dts = src->dts;
@@ -382,9 +386,16 @@ int av_packet_copy_props(AVPacket *dst, const AVPacket *src)
dst->duration = src->duration;
dst->flags = src->flags;
dst->stream_index = src->stream_index;
-
+ dst->opaque = src->opaque;
+ dst->time_base = src->time_base;
+ dst->opaque_ref = NULL;
dst->side_data = NULL;
dst->side_data_elems = 0;
+
+ ret = av_buffer_replace(&dst->opaque_ref, src->opaque_ref);
+ if (ret < 0)
+ return ret;
+
for (i = 0; i < src->side_data_elems; i++) {
enum AVPacketSideDataType type = src->side_data[i].type;
size_t size = src->side_data[i].size;
@@ -392,6 +403,7 @@ int av_packet_copy_props(AVPacket *dst, const AVPacket *src)
uint8_t *dst_data = av_packet_new_side_data(dst, type, size);
if (!dst_data) {
+ av_buffer_unref(&dst->opaque_ref);
av_packet_free_side_data(dst);
return AVERROR(ENOMEM);
}
@@ -404,6 +416,7 @@ int av_packet_copy_props(AVPacket *dst, const AVPacket *src)
void av_packet_unref(AVPacket *pkt)
{
av_packet_free_side_data(pkt);
+ av_buffer_unref(&pkt->opaque_ref);
av_buffer_unref(&pkt->buf);
get_packet_defaults(pkt);
}
diff --git a/libavcodec/packet.h b/libavcodec/packet.h
index a9d3a9b596..9baff24635 100644
--- a/libavcodec/packet.h
+++ b/libavcodec/packet.h
@@ -391,6 +391,27 @@ typedef struct AVPacket {
int64_t duration;
int64_t pos; ///< byte position in stream, -1 if unknown
+
+ /**
+ * for some private data of the user
+ */
+ void *opaque;
+
+ /**
+ * AVBufferRef for free use by the API user. FFmpeg will never check the
+ * contents of the buffer ref. FFmpeg calls av_buffer_unref() on it when
+ * the packet is unreferenced. av_packet_copy_props() calls create a new
+ * reference with av_buffer_ref() for the target packet's opaque_ref field.
+ *
+ * This is unrelated to the opaque field, although it serves a similar
+ * purpose.
+ */
+ AVBufferRef *opaque_ref;
+
+ /**
+ * Time base of the packet's timestamps.
+ */
+ AVRational time_base;
} AVPacket;
#if FF_API_INIT_PACKET
--
2.32.0.272.g935e593368
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