On Sun, Mar 25, 2018 at 10:41 AM, Mark Thompson <s...@jkqxz.net> wrote:
> Allows extraction (to side data) and removal of closed captions in
> user data blocks.
> ---
> doc/bitstream_filters.texi | 12 ++++++
> libavcodec/Makefile | 2 +-
> libavcodec/mpeg2_metadata_bsf.c | 81 ++++++++++++++++++++++++++++++
> ++++++++++-
> 3 files changed, 93 insertions(+), 2 deletions(-)
>
> diff --git a/doc/bitstream_filters.texi b/doc/bitstream_filters.texi
> index 41424cf42f..f115f7b0c5 100644
> --- a/doc/bitstream_filters.texi
> +++ b/doc/bitstream_filters.texi
> @@ -465,6 +465,18 @@ table 6-6).
> Set the colour description in the stream (see H.262 section 6.3.6
> and tables 6-7, 6-8 and 6-9).
>
> +@item a53_cc
> +Modify A/53 closed captions in user data blocks.
> +
> +@table @samp
> +@item remove
> +Remove all closed caption data from the stream.
> +
> +@item extract
> +Extract closed captions from the stream so that they are available as
> +as packet side data.
> +@end table
> +
> @end table
>
> @section mpeg4_unpack_bframes
> diff --git a/libavcodec/Makefile b/libavcodec/Makefile
> index cfde104055..e5430ab10b 100644
> --- a/libavcodec/Makefile
> +++ b/libavcodec/Makefile
> @@ -1057,7 +1057,7 @@ OBJS-$(CONFIG_MPEG4_UNPACK_BFRAMES_BSF) +=
> mpeg4_unpack_bframes_bsf.o
> OBJS-$(CONFIG_MOV2TEXTSUB_BSF) += movsub_bsf.o
> OBJS-$(CONFIG_MP3_HEADER_DECOMPRESS_BSF) += mp3_header_decompress_bsf.o
> \
> mpegaudiodata.o
> -OBJS-$(CONFIG_MPEG2_METADATA_BSF) += mpeg2_metadata_bsf.o
> +OBJS-$(CONFIG_MPEG2_METADATA_BSF) += mpeg2_metadata_bsf.o
> cbs_misc.o
> OBJS-$(CONFIG_NOISE_BSF) += noise_bsf.o
> OBJS-$(CONFIG_NULL_BSF) += null_bsf.o
> OBJS-$(CONFIG_REMOVE_EXTRADATA_BSF) += remove_extradata_bsf.o
> diff --git a/libavcodec/mpeg2_metadata_bsf.c b/libavcodec/mpeg2_metadata_
> bsf.c
> index e787cb3782..49335d7fcb 100644
> --- a/libavcodec/mpeg2_metadata_bsf.c
> +++ b/libavcodec/mpeg2_metadata_bsf.c
> @@ -22,9 +22,17 @@
>
> #include "bsf.h"
> #include "cbs.h"
> +#include "cbs_misc.h"
> #include "cbs_mpeg2.h"
> #include "mpeg12.h"
>
> +enum {
> + PASS,
> + INSERT,
> + REMOVE,
> + EXTRACT,
> +};
> +
> typedef struct MPEG2MetadataContext {
> const AVClass *class;
>
> @@ -42,6 +50,8 @@ typedef struct MPEG2MetadataContext {
> int transfer_characteristics;
> int matrix_coefficients;
>
> + int a53_cc;
> +
> int mpeg1_warned;
> } MPEG2MetadataContext;
>
> @@ -184,7 +194,9 @@ static int mpeg2_metadata_filter(AVBSFContext *bsf,
> AVPacket *out)
> MPEG2MetadataContext *ctx = bsf->priv_data;
> AVPacket *in = NULL;
> CodedBitstreamFragment *frag = &ctx->fragment;
> - int err;
> + int err, i;
> + uint8_t *a53_side_data = NULL;
> + size_t a53_side_data_size = 0;
>
> err = ff_bsf_get_packet(bsf, &in);
> if (err < 0)
> @@ -202,6 +214,51 @@ static int mpeg2_metadata_filter(AVBSFContext *bsf,
> AVPacket *out)
> goto fail;
> }
>
> + if (ctx->a53_cc == REMOVE || ctx->a53_cc == EXTRACT) {
> + for (i = 0; i < frag->nb_units; i++) {
> + MPEG2RawUserData *ud;
> + A53UserData a53_ud;
> +
> + if (frag->units[i].type != MPEG2_START_USER_DATA)
> + continue;
> + ud = frag->units[i].content;
> +
> + err = ff_cbs_read_a53_user_data(ctx->cbc, &a53_ud,
> ud->user_data,
> + ud->user_data_length);
> + 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;
> + }
> +
> + if (ctx->a53_cc == REMOVE) {
> + err = ff_cbs_delete_unit(ctx->cbc, frag, i);
> + if (err < 0) {
> + av_log(bsf, AV_LOG_ERROR, "Failed to delete "
> + "A/53 CC user data.\n");
> + goto fail;
> + }
> + --i;
> + break;
> + } else if(ctx->a53_cc == EXTRACT) {
> + err = ff_cbs_write_a53_cc_side_data(ctx->cbc,
> + &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");
> + goto fail;
> + }
> + }
> + }
> + }
> +
> err = ff_cbs_write_packet(ctx->cbc, out, frag);
> if (err < 0) {
> av_log(bsf, AV_LOG_ERROR, "Failed to write packet.\n");
> @@ -212,9 +269,21 @@ static int mpeg2_metadata_filter(AVBSFContext *bsf,
> AVPacket *out)
> if (err < 0)
> goto fail;
>
> + if (a53_side_data) {
> + err = av_packet_add_side_data(out, 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");
> + goto fail;
> + }
> + a53_side_data = NULL;
> + }
> +
> err = 0;
> fail:
> ff_cbs_fragment_uninit(ctx->cbc, frag);
> + av_freep(&a53_side_data);
>
> if (err < 0)
> av_packet_unref(out);
> @@ -289,6 +358,16 @@ static const AVOption mpeg2_metadata_options[] = {
> OFFSET(matrix_coefficients), AV_OPT_TYPE_INT,
> { .i64 = -1 }, -1, 255, FLAGS },
>
> + { "a53_cc", "A/53 Closed Captions in user data",
> + OFFSET(a53_cc), AV_OPT_TYPE_INT,
> + { .i64 = PASS }, PASS, EXTRACT, FLAGS, "a53_cc" },
> + { "pass", NULL, 0, AV_OPT_TYPE_CONST,
> + { .i64 = PASS }, .flags = FLAGS, .unit = "a53_cc" },
> + { "remove", NULL, 0, AV_OPT_TYPE_CONST,
> + { .i64 = REMOVE }, .flags = FLAGS, .unit = "a53_cc" },
> + { "extract", NULL, 0, AV_OPT_TYPE_CONST,
> + { .i64 = EXTRACT }, .flags = FLAGS, .unit = "a53_cc" },
> +
> { NULL }
> };
>
LGTM, thanks for refactoring!
Aman
>
> --
> 2.16.1
>
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> ffmpeg-devel@ffmpeg.org
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