On 12/03/18 15:10, Hendrik Leppkes wrote:
> 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.

Each packet is being tagged with the side-data extracted from the contents of 
that packet.  Like the non-side-data part of a packet, this needs to be passed 
through a decoder (of some kind) to turn a packet into a frame before you can 
display it sensibly.

> 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?
As with the decoder case, it can work with any encoder which can match output 
packets to input frames.  (I haven't sent any patches to pass side-data through 
an encoder yet, but I plan to do so at least for VAAPI.)

- Mark
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