On Mon, Mar 12, 2018 at 2:38 PM, Mark Thompson <s...@jkqxz.net> wrote:
> On 12/03/18 09:54, Hendrik Leppkes wrote:
>> On Sun, Mar 11, 2018 at 7:30 PM, Mark Thompson <s...@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);
>>> +
>>> + 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" },
>>> +
>>
>> Does extracting really make sense? Doesn't the data end up out of
>> order and basically unusable?
>
> Well, it's up to whatever follows to deal with that. If the stream has
> correct timesatamps (ha) then you can use those directly. If you're feeding
> the output to an opaque hardware decoder then having some way to associate
> input packets with output frames is sufficient to get the right ordering. A
> BSF to deal with reordering somehow is also possible.
>
That seems like a problem. You generate side-data like any other, but
in reality its invalid, and if you process it like any other A53
sidedata you get corrupt output.
The same goes for "insert", I guess, how do I figure out in which
order to pass things to it to get any sort of functional output? Thats
a very specific setup which requires extremely custom and careful
usage, does that really fit in a generic filter?
- Hendrik
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