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avcodec/cbs_sei: Use RefStruct API for SEI messages 

The SEI message code uses the AVBuffer API for its SEI messages
and contained buffers (like the extension buffer for HEVC
or the user data (un)registered payload buffers).

Contrary to the ordinary CBS code (where some of these
contained buffer references are actually references
to the provided AVPacket's data so that one can't replace
them with the RefStruct API), the CBS SEI code never uses
outside buffers at all and can therefore be switched entirely
to the RefStruct API. This avoids the overhead inherent
in the AVBuffer API (namely the separate allocations etc.).

Notice that the refcounting here is actually currently unused;
the refcounts are always one (or zero in case of no refcounting);
its only advantage is the flexibility provided by custom
free functions.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
This commit is contained in:
Andreas Rheinhardt 2023-09-13 01:01:16 +02:00
parent 3e9b8d14e5
commit 3ba4f9c21e
4 changed files with 55 additions and 52 deletions
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21
libavcodec/cbs_h2645.c
View File

@ -331,6 +331,23 @@ static int cbs_h2645_read_more_rbsp_data(GetBitContext *gbc)
#define bit_position(rw) (get_bits_count(rw))
#define byte_alignment(rw) (get_bits_count(rw) % 8)
/* The CBS SEI code uses the refstruct API for the allocation
* of its child buffers. */
#define allocate(name, size) do { \
name = ff_refstruct_allocz(size + \
AV_INPUT_BUFFER_PADDING_SIZE); \
if (!name) \
return AVERROR(ENOMEM); \
} while (0)
#define FUNC(name) FUNC_SEI(name)
#include "cbs_sei_syntax_template.c"
#undef FUNC
#undef allocate
/* The other code uses the refstruct API for the allocation
* of its child buffers. */
#define allocate(name, size) do { \
name ## _ref = av_buffer_allocz(size + \
AV_INPUT_BUFFER_PADDING_SIZE); \
@ -339,10 +356,6 @@ static int cbs_h2645_read_more_rbsp_data(GetBitContext *gbc)
name = name ## _ref->data; \
} while (0)
#define FUNC(name) FUNC_SEI(name)
#include "cbs_sei_syntax_template.c"
#undef FUNC
#define FUNC(name) FUNC_H264(name)
#include "cbs_h264_syntax_template.c"
#undef FUNC

61
libavcodec/cbs_sei.c
View File

@ -22,25 +22,25 @@
#include "cbs_h265.h"
#include "cbs_h266.h"
#include "cbs_sei.h"
#include "refstruct.h"
static void cbs_free_user_data_registered(void *opaque, uint8_t *data)
static void cbs_free_user_data_registered(FFRefStructOpaque unused, void *obj)
{
SEIRawUserDataRegistered *udr = (SEIRawUserDataRegistered*)data;
av_buffer_unref(&udr->data_ref);
av_free(udr);
SEIRawUserDataRegistered *udr = obj;
ff_refstruct_unref(&udr->data);
}
static void cbs_free_user_data_unregistered(void *opaque, uint8_t *data)
static void cbs_free_user_data_unregistered(FFRefStructOpaque unused, void *obj)
{
SEIRawUserDataUnregistered *udu = (SEIRawUserDataUnregistered*)data;
av_buffer_unref(&udu->data_ref);
av_free(udu);
SEIRawUserDataUnregistered *udu = obj;
ff_refstruct_unref(&udu->data);
}
int ff_cbs_sei_alloc_message_payload(SEIRawMessage *message,
const SEIMessageTypeDescriptor *desc)
{
void (*free_func)(void*, uint8_t*);
void (*free_func)(FFRefStructOpaque, void*);
unsigned flags = 0;
av_assert0(message->payload == NULL &&
message->payload_ref == NULL);
@ -50,24 +50,16 @@ int ff_cbs_sei_alloc_message_payload(SEIRawMessage *message,
free_func = &cbs_free_user_data_registered;
else if (desc->type == SEI_TYPE_USER_DATA_UNREGISTERED)
free_func = &cbs_free_user_data_unregistered;
else
else {
free_func = NULL;
flags = FF_REFSTRUCT_FLAG_NO_ZEROING;
}
if (free_func) {
message->payload = av_mallocz(desc->size);
if (!message->payload)
return AVERROR(ENOMEM);
message->payload_ref =
av_buffer_create(message->payload, desc->size,
free_func, NULL, 0);
} else {
message->payload_ref = av_buffer_alloc(desc->size);
}
if (!message->payload_ref) {
av_freep(&message->payload);
message->payload_ref = ff_refstruct_alloc_ext(desc->size, flags,
NULL, free_func);
if (!message->payload_ref)
return AVERROR(ENOMEM);
}
message->payload = message->payload_ref->data;
message->payload = message->payload_ref;
return 0;
}
@ -101,8 +93,8 @@ void ff_cbs_sei_free_message_list(SEIRawMessageList *list)
{
for (int i = 0; i < list->nb_messages; i++) {
SEIRawMessage *message = &list->messages[i];
av_buffer_unref(&message->payload_ref);
av_buffer_unref(&message->extension_data_ref);
ff_refstruct_unref(&message->payload_ref);
ff_refstruct_unref(&message->extension_data);
}
av_free(list->messages);
}
@ -278,13 +270,12 @@ int ff_cbs_sei_add_message(CodedBitstreamContext *ctx,
int prefix,
uint32_t payload_type,
void *payload_data,
AVBufferRef *payload_buf)
void *payload_ref)
{
const SEIMessageTypeDescriptor *desc;
CodedBitstreamUnit *unit;
SEIRawMessageList *list;
SEIRawMessage *message;
AVBufferRef *payload_ref;
int err;
desc = ff_cbs_sei_find_type(ctx, payload_type);
@ -306,12 +297,10 @@ int ff_cbs_sei_add_message(CodedBitstreamContext *ctx,
if (err < 0)
return err;
if (payload_buf) {
payload_ref = av_buffer_ref(payload_buf);
if (!payload_ref)
return AVERROR(ENOMEM);
} else {
payload_ref = NULL;
if (payload_ref) {
/* The following just increments payload_ref's refcount,
* so that payload_ref is now owned by us. */
payload_ref = ff_refstruct_ref(payload_ref);
}
message = &list->messages[list->nb_messages - 1];
@ -364,8 +353,8 @@ static void cbs_sei_delete_message(SEIRawMessageList *list,
av_assert0(0 <= position && position < list->nb_messages);
message = &list->messages[position];
av_buffer_unref(&message->payload_ref);
av_buffer_unref(&message->extension_data_ref);
ff_refstruct_unref(&message->payload_ref);
ff_refstruct_unref(&message->extension_data);
--list->nb_messages;

20
libavcodec/cbs_sei.h
View File

@ -22,8 +22,6 @@
#include <stddef.h>
#include <stdint.h>
#include "libavutil/buffer.h"
#include "cbs.h"
#include "sei.h"
@ -35,15 +33,13 @@ typedef struct SEIRawFillerPayload {
typedef struct SEIRawUserDataRegistered {
uint8_t itu_t_t35_country_code;
uint8_t itu_t_t35_country_code_extension_byte;
uint8_t *data;
AVBufferRef *data_ref;
uint8_t *data; ///< RefStruct reference
size_t data_length;
} SEIRawUserDataRegistered;
typedef struct SEIRawUserDataUnregistered {
uint8_t uuid_iso_iec_11578[16];
uint8_t *data;
AVBufferRef *data_ref;
uint8_t *data; ///< RefStruct reference
size_t data_length;
} SEIRawUserDataUnregistered;
@ -75,9 +71,8 @@ typedef struct SEIRawMessage {
uint32_t payload_type;
uint32_t payload_size;
void *payload;
AVBufferRef *payload_ref;
uint8_t *extension_data;
AVBufferRef *extension_data_ref;
void *payload_ref; ///< RefStruct reference
uint8_t *extension_data; ///< RefStruct reference
size_t extension_bit_length;
} SEIRawMessage;
@ -174,15 +169,16 @@ void ff_cbs_sei_free_message_list(SEIRawMessageList *list);
* Will add to an existing SEI NAL unit, or create a new one for the
* message if there is no suitable existing one.
*
* Takes a new reference to payload_buf, if set. If payload_buf is
* NULL then the new message will not be reference counted.
* If set, payload_ref must be a RefStruct reference backing payload_data.
* This function creates a new reference to payload_ref in this case.
* If payload_ref is NULL, the new message will not be reference counted.
*/
int ff_cbs_sei_add_message(CodedBitstreamContext *ctx,
CodedBitstreamFragment *au,
int prefix,
uint32_t payload_type,
void *payload_data,
AVBufferRef *payload_buf);
void *payload_ref);
/**
* Iterate over messages with the given payload type in an access unit.

5
libavcodec/cbs_sei_syntax_template.c
View File

@ -234,7 +234,12 @@ static int FUNC(message)(CodedBitstreamContext *ctx, RWContext *rw,
} else {
uint8_t *data;
#ifdef READ
allocate(current->payload_ref, current->payload_size);
current->payload = current->payload_ref;
#else
allocate(current->payload, current->payload_size);
#endif
data = current->payload;
for (i = 0; i < current->payload_size; i++)