[FFmpeg-devel] [PATCH 4/8] h264_metadata: Add support for A/53 closed captions
Aman Gupta
ffmpeg at tmm1.net
Mon Mar 12 09:19:51 EET 2018
On Sun, Mar 11, 2018 at 11:30 AM, Mark Thompson <sw at jkqxz.net> wrote:
> ---
> libavcodec/h264_metadata_bsf.c | 121 ++++++++++++++++++++++++++++++
> +++++++++++
> 1 file changed, 121 insertions(+)
>
> diff --git a/libavcodec/h264_metadata_bsf.c b/libavcodec/h264_metadata_
> bsf.c
> index 36047887ca..d340c55990 100644
> --- a/libavcodec/h264_metadata_bsf.c
> +++ b/libavcodec/h264_metadata_bsf.c
> @@ -77,6 +77,8 @@ typedef struct H264MetadataContext {
> int display_orientation;
> double rotate;
> int flip;
> +
> + int a53_cc;
> } H264MetadataContext;
>
>
> @@ -225,6 +227,8 @@ static int h264_metadata_filter(AVBSFContext *bsf,
> AVPacket *out)
> int err, i, j, has_sps;
> uint8_t *displaymatrix_side_data = NULL;
> size_t displaymatrix_side_data_size = 0;
> + uint8_t *a53_side_data = NULL;
> + size_t a53_side_data_size = 0;
>
> err = ff_bsf_get_packet(bsf, &in);
> if (err < 0)
> @@ -514,6 +518,104 @@ static int h264_metadata_filter(AVBSFContext *bsf,
> AVPacket *out)
> }
> }
>
> + if (ctx->a53_cc == INSERT) {
> + uint8_t *data;
> + int size;
> +
> + data = av_packet_get_side_data(in, AV_PKT_DATA_A53_CC, &size);
> + if (data) {
> + H264RawSEIPayload payload = {
> + .payload_type = H264_SEI_TYPE_USER_DATA_REGISTERED,
> + };
> + H264RawSEIUserDataRegistered *udr =
> + &payload.payload.user_data_registered;
> +
> + av_log(bsf, AV_LOG_WARNING, "A53 CC insert: %d bytes.\n",
> size);
> +
> + udr->data_length = size + 10;
> + udr->data_ref = av_buffer_alloc(udr->data_length);
> + if (!udr->data_ref) {
> + err = AVERROR(ENOMEM);
> + goto fail;
> + }
> + udr->data = udr->data_ref->data;
> +
> + udr->itu_t_t35_country_code = 181;
> + udr->data[0] = 0;
> + udr->data[1] = 49;
> + AV_WB32(udr->data + 2, MKBETAG('G', 'A', '9', '4'));
> + udr->data[6] = 3;
> + udr->data[7] = ((size / 3) & 0x1f) | 0x40;
> + udr->data[8] = 0;
> + memcpy(udr->data + 9, data, size);
> + udr->data[size + 9] = 0xff;
> +
> + err = ff_cbs_h264_add_sei_message(ctx->cbc, au, &payload);
> + if (err < 0) {
> + av_log(bsf, AV_LOG_ERROR, "Failed to add user data SEI "
> + "message to access unit.\n");
> + av_buffer_unref(&udr->data_ref);
> + goto fail;
> + }
> + }
> +
> + } else if (ctx->a53_cc == REMOVE || ctx->a53_cc == EXTRACT) {
> + for (i = 0; i < au->nb_units; i++) {
> + H264RawSEI *sei;
> + if (au->units[i].type != H264_NAL_SEI)
> + continue;
> + sei = au->units[i].content;
> +
> + for (j = 0; j < sei->payload_count; j++) {
> + H264RawSEIUserDataRegistered *udr;
> + uint32_t tag;
> + uint8_t type_code, count;
> +
> + if (sei->payload[j].payload_type !=
> + H264_SEI_TYPE_USER_DATA_REGISTERED)
> + continue;
> + udr = &sei->payload[j].payload.user_data_registered;
> + tag = AV_RB32(udr->data + 2);
> + type_code = udr->data[6];
> + if (tag != MKBETAG('G', 'A', '9', '4') || type_code != 3)
> + continue;
> +
> + if (ctx->a53_cc == REMOVE) {
> + err = ff_cbs_h264_delete_sei_message(ctx->cbc, au,
> + &au->units[i],
> j);
> + if (err < 0) {
> + av_log(bsf, AV_LOG_ERROR, "Failed to delete "
> + "A53 CC SEI message.\n");
> + goto fail;
> + }
> + av_log(bsf, AV_LOG_WARNING, "A53 CC remove!.\n");
+
> + --i;
> + break;
> + }
> +
> + // Extract.
> + count = udr->data[7] & 0x1f;
> + if (3 * count + 10 > udr->data_length) {
> + av_log(bsf, AV_LOG_ERROR, "Invalid A/53 closed
> caption "
> + "data: count %d overflows length %zu.\n",
> + count, udr->data_length);
> + continue;
> + }
> +
> + av_log(bsf, AV_LOG_WARNING, "A53 CC extract: %zu
> bytes.\n", udr->data_length);
>
I assume these are WARNINGs from testing? Seems like TRACE or DEBUG would
be fine.
> +
> + err = av_reallocp(&a53_side_data,
> + a53_side_data_size + 3 * count);
> + if (err)
> + goto fail;
> + memcpy(a53_side_data + a53_side_data_size,
> + udr->data + 9, 3 * count);
> + a53_side_data_size += 3 * count;
> + }
> + }
> + }
> +
> err = ff_cbs_write_packet(ctx->cbc, out, au);
> if (err < 0) {
> av_log(bsf, AV_LOG_ERROR, "Failed to write packet.\n");
> @@ -535,6 +637,16 @@ static int h264_metadata_filter(AVBSFContext *bsf,
> AVPacket *out)
> }
> displaymatrix_side_data = NULL;
> }
> + 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;
> + }
>
> ctx->done_first_au = 1;
>
> @@ -542,6 +654,7 @@ static int h264_metadata_filter(AVBSFContext *bsf,
> AVPacket *out)
> fail:
> ff_cbs_fragment_uninit(ctx->cbc, au);
> av_freep(&displaymatrix_side_data);
> + av_freep(&a53_side_data);
>
> av_packet_free(&in);
>
> @@ -670,6 +783,14 @@ static const AVOption h264_metadata_options[] = {
> { "vertical", "Set ver_flip",
> 0, AV_OPT_TYPE_CONST, { .i64 = FLIP_VERTICAL }, .unit ="flip" },
>
> + { "a53_cc", "A/53 Closed Captions in SEI NAL units",
> + OFFSET(a53_cc), AV_OPT_TYPE_INT,
> + { .i64 = PASS }, PASS, EXTRACT, 0, "a53_cc" },
> + { "pass", NULL, 0, AV_OPT_TYPE_CONST, { .i64 = PASS }, .unit =
> "a53_cc" },
> + { "insert", NULL, 0, AV_OPT_TYPE_CONST, { .i64 = INSERT }, .unit =
> "a53_cc" },
> + { "remove", NULL, 0, AV_OPT_TYPE_CONST, { .i64 = REMOVE }, .unit =
> "a53_cc" },
> + { "extract", NULL, 0, AV_OPT_TYPE_CONST, { .i64 = EXTRACT }, .unit =
> "a53_cc" },
>
Thanks for writing this patch!
I tested the remove and extract modes on a h264 stream and they work as
expected.
I was also able to port these over to the mpeg2_metadata bsf and will
submit a patch shortly.
Aman
> +
> { NULL }
> };
>
> --
> 2.16.1
>
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