[FFmpeg-devel] [PATCH 4/8] h264_metadata: Add support for A/53 closed captions
Mark Thompson
sw at jkqxz.net
Mon Mar 12 15:26:01 EET 2018
On 12/03/18 07:19, Aman Gupta wrote:
> 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.
Oops, yeah. Removed this one and others.
(The filter probably does want some more logging to explain what it's doing (at VERBOSE or DEBUG?), but not like this.)
>> +
>> + 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.
Yay!
> I was also able to port these over to the mpeg2_metadata bsf and will
> submit a patch shortly.
I wonder whether this should be put further into cbs to avoid duplication, since presumably H.265 would want identical code as well. Maybe cbs_misc.c with template code for reading/writing MPEG-2 user_data and H.264 (and H.265) user_data_registered in the same way?
Thanks,
- Mark
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