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avcodec/h265_metadata_bsf: add support for a/53 closed captions
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Signed-off-by: Aman Karmani <aman@tmm1.net>
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@tmm1
tmm1 committed Feb 4, 2023
1 parent d79635a commit 8aa6c32
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Showing 3 changed files with 156 additions and 1 deletion.
11 changes: 11 additions & 0 deletions doc/bitstream_filters.texi
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Expand Up @@ -398,6 +398,17 @@ confuse other transformations which require correct extradata.
Modify metadata embedded in an HEVC stream.

@table @option
@item a53_cc
Insert or remove registered userdata SEI NAL units containing A/53 closed captions.

@table @samp
@item pass
@item insert
@item remove
@end table

Default is pass.

@item aud
Insert or remove AUD NAL units in all access units of the stream.

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2 changes: 1 addition & 1 deletion libavcodec/Makefile
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Expand Up @@ -1217,7 +1217,7 @@ OBJS-$(CONFIG_H264_MP4TOANNEXB_BSF) += h264_mp4toannexb_bsf.o
OBJS-$(CONFIG_H264_REDUNDANT_PPS_BSF) += h264_redundant_pps_bsf.o
OBJS-$(CONFIG_HAPQA_EXTRACT_BSF) += hapqa_extract_bsf.o hap.o
OBJS-$(CONFIG_HEVC_METADATA_BSF) += h265_metadata_bsf.o h265_profile_level.o \
h2645data.o
h2645data.o cbs_misc.o
OBJS-$(CONFIG_HEVC_MP4TOANNEXB_BSF) += hevc_mp4toannexb_bsf.o
OBJS-$(CONFIG_IMX_DUMP_HEADER_BSF) += imx_dump_header_bsf.o
OBJS-$(CONFIG_MEDIA100_TO_MJPEGB_BSF) += media100_to_mjpegb_bsf.o
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144 changes: 144 additions & 0 deletions libavcodec/h265_metadata_bsf.c
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Expand Up @@ -24,6 +24,8 @@
#include "cbs.h"
#include "cbs_bsf.h"
#include "cbs_h265.h"
#include "cbs_misc.h"
#include "cbs_sei.h"
#include "h2645data.h"
#include "hevc.h"
#include "h265_profile_level.h"
Expand Down Expand Up @@ -62,6 +64,7 @@ typedef struct H265MetadataContext {
int level;
int level_guess;
int level_warned;
int a53_cc;
} H265MetadataContext;


Expand Down Expand Up @@ -322,6 +325,137 @@ static int h265_metadata_update_sps(AVBSFContext *bsf,
return 0;
}

static int h265_metadata_extract_a53_cc(AVBSFContext *bsf, AVPacket *pkt,
CodedBitstreamFragment *au)
{
H265MetadataContext *ctx = bsf->priv_data;
SEIRawMessage *message;
int err;

message = NULL;
while (ff_cbs_sei_find_message(ctx->common.output, au,
SEI_TYPE_USER_DATA_REGISTERED_ITU_T_T35,
&message) == 0) {
SEIRawUserDataRegistered *udr = message->payload;
A53UserData a53_ud;
uint8_t *a53_side_data = NULL;
size_t a53_side_data_size = 0;

if (udr->data_length < 2) {
// Too short to contain a provider code.
continue;
}

if (AV_RB16(udr->data) != 0x31) { // provider_code as atsc_provider_code
// Not ATSC.
continue;
}

// The first two bytes of the message is provider_code
err = ff_cbs_read_a53_user_data(ctx->common.output,
&a53_ud,
udr->data + 2,
udr->data_length - 2);
if (err < 0) {
// Invalid or something completely different.
continue;
}
if (a53_ud.user_identifier != A53_USER_IDENTIFIER_ATSC ||
a53_ud.atsc.user_data_type_code !=
A53_USER_DATA_TYPE_CODE_CC_DATA) {
// Valid but something else (e.g. AFD).
continue;
}

err = ff_cbs_write_a53_cc_side_data(ctx->common.output,
&a53_side_data,
&a53_side_data_size,
&a53_ud);
if (err < 0) {
av_log(bsf, AV_LOG_ERROR, "Failed to write "
"A/53 user data for packet side data.\n");
return err;
}

if (a53_side_data) {
err = av_packet_add_side_data(pkt, AV_PKT_DATA_A53_CC,
a53_side_data, a53_side_data_size);
if (err) {
av_log(bsf, AV_LOG_ERROR, "Failed to attach extracted A/53 "
"side data to packet.\n");
av_freep(&a53_side_data);
return err;
}

if (ctx->a53_cc == BSF_ELEMENT_REMOVE ||
ctx->a53_cc == BSF_ELEMENT_INSERT) {
ff_cbs_sei_delete_message(ctx->common.output, au, message);

// Reset iteration
message = NULL;
}
}
}

if (ctx->a53_cc == BSF_ELEMENT_INSERT) {
uint8_t *data;
size_t size;
int offset = 0;

data = av_packet_get_side_data(pkt, AV_PKT_DATA_A53_CC, &size);
while (size > 0) {
A53UserData a53_ud;
int rsize = FFMIN(93, size);

err = ff_cbs_read_a53_cc_side_data(ctx->common.output, &a53_ud,
data + offset, rsize);
offset += rsize;
size -= rsize;
if (err < 0) {
av_log(bsf, AV_LOG_WARNING, "Invalid A/53 closed captions "
"in packet side data dropped.\n");
} else {
AVBufferRef *udr_buf = av_buffer_allocz(sizeof(SEIRawUserDataRegistered));
SEIRawUserDataRegistered *udr = (SEIRawUserDataRegistered*)udr_buf->data;
size_t size = 9 + 3 * a53_ud.atsc.cc_data.cc_count;

udr->data_ref = av_buffer_allocz(2 + size);
if (!udr->data_ref) {
return AVERROR(ENOMEM);
}
udr->data = udr->data_ref->data;
udr->data_length = udr->data_ref->size;

udr->itu_t_t35_country_code = 0xB5; // usa_country_code
AV_WB16(udr->data, 0x31); // provider_code as atsc_provider_code

err = ff_cbs_write_a53_user_data(ctx->common.output, udr->data + 2,
&size, &a53_ud);
if (err < 0) {
av_log(bsf, AV_LOG_ERROR, "Failed to write "
"A/53 user data.\n");
av_buffer_unref(&udr->data_ref);
av_buffer_unref(&udr_buf);
return err;
}

err = ff_cbs_sei_add_message(ctx->common.output, au, 1,
SEI_TYPE_USER_DATA_REGISTERED_ITU_T_T35,
udr, udr_buf);
if (err < 0) {
av_log(bsf, AV_LOG_ERROR, "Failed to add A/53 user data "
"SEI message to access unit.\n");
av_buffer_unref(&udr->data_ref);
av_buffer_unref(&udr_buf);
return err;
}
}
}
}

return 0;
}

static int h265_metadata_update_fragment(AVBSFContext *bsf, AVPacket *pkt,
CodedBitstreamFragment *au)
{
Expand Down Expand Up @@ -387,6 +521,12 @@ static int h265_metadata_update_fragment(AVBSFContext *bsf, AVPacket *pkt,
}
}

if (pkt && ctx->a53_cc != BSF_ELEMENT_PASS) {
err = h265_metadata_extract_a53_cc(bsf, pkt, au);
if (err < 0)
return err;
}

return 0;
}

Expand Down Expand Up @@ -478,6 +618,10 @@ static const AVOption h265_metadata_options[] = {
{ LEVEL("8.5", 255) },
#undef LEVEL

BSF_ELEMENT_OPTIONS_PIRE("a53_cc",
"A/53 Closed Captions in SEI NAL units",
a53_cc, FLAGS),

{ NULL }
};

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