[FFmpeg-devel] [PATCH 6/6] decklink: Add support for SCTE-104 to decklink capture

Devin Heitmueller dheitmueller at ltnglobal.com
Thu Nov 16 20:34:17 EET 2017


Make use of libklvanc to parse SCTE-104 packets and announce them
as a new stream.  Right now we just pass the payload straight
through, but once this is hoooked into libklscte35 we'll be able
to generate SCTE-35 messages in the MPEG TS stream.

Note that this feature needs to be explicitly enabled by the user
through the "-enable_scte_104" option, since we cannot autodetect
the presence of SCTE-104 (because unlike with 708/AFD messages are
not set except when trigger occurs, thus the stream wouldn't get
created during the read_header phase).

Signed-off-by: Devin Heitmueller <dheitmueller at ltnglobal.com>
---
 libavcodec/avcodec.h            |  1 +
 libavcodec/codec_desc.c         |  6 ++++
 libavdevice/decklink_common.h   |  6 ++++
 libavdevice/decklink_common_c.h |  1 +
 libavdevice/decklink_dec.cpp    | 64 ++++++++++++++++++++++++++++++++++++++++-
 libavdevice/decklink_dec_c.c    |  1 +
 6 files changed, 78 insertions(+), 1 deletion(-)

diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
index 6981f07..453b6be 100644
--- a/libavcodec/avcodec.h
+++ b/libavcodec/avcodec.h
@@ -667,6 +667,7 @@ enum AVCodecID {
     AV_CODEC_ID_TTF = 0x18000,
 
     AV_CODEC_ID_SCTE_35, ///< Contain timestamp estimated through PCR of program stream.
+    AV_CODEC_ID_SCTE_104,
     AV_CODEC_ID_BINTEXT    = 0x18800,
     AV_CODEC_ID_XBIN,
     AV_CODEC_ID_IDF,
diff --git a/libavcodec/codec_desc.c b/libavcodec/codec_desc.c
index c3688de..e198985 100644
--- a/libavcodec/codec_desc.c
+++ b/libavcodec/codec_desc.c
@@ -3103,6 +3103,12 @@ static const AVCodecDescriptor codec_descriptors[] = {
         .name      = "scte_35",
         .long_name = NULL_IF_CONFIG_SMALL("SCTE 35 Message Queue"),
     },
+    {
+        .id        = AV_CODEC_ID_SCTE_104,
+        .type      = AVMEDIA_TYPE_DATA,
+        .name      = "scte_104",
+        .long_name = NULL_IF_CONFIG_SMALL("SCTE 104 Digital Program Insertion"),
+    },
 
     /* deprecated codec ids */
 };
diff --git a/libavdevice/decklink_common.h b/libavdevice/decklink_common.h
index bbe4deb..3ecdb19 100644
--- a/libavdevice/decklink_common.h
+++ b/libavdevice/decklink_common.h
@@ -35,6 +35,10 @@
    Actual number for any particular model of card may be lower */
 #define DECKLINK_MAX_AUDIO_CHANNELS 32
 
+/* This isn't actually tied to the Blackmagic hardware - it's an arbitrary
+   number used to size the array of streams */
+#define DECKLINK_MAX_DATA_STREAMS 16
+
 class decklink_output_callback;
 class decklink_input_callback;
 
@@ -86,6 +90,8 @@ struct decklink_ctx {
     unsigned int dropped;
     AVStream *audio_st[DECKLINK_MAX_AUDIO_CHANNELS];
     int num_audio_streams;
+    AVStream *data_st[DECKLINK_MAX_DATA_STREAMS];
+    int num_data_streams;
     AVStream *video_st;
     AVStream *teletext_st;
     uint16_t cdp_sequence_num;
diff --git a/libavdevice/decklink_common_c.h b/libavdevice/decklink_common_c.h
index 02011ed..cb73ec9 100644
--- a/libavdevice/decklink_common_c.h
+++ b/libavdevice/decklink_common_c.h
@@ -58,6 +58,7 @@ struct decklink_cctx {
     char *format_code;
     int raw_format;
     int64_t queue_size;
+    int enable_scte_104;
 };
 
 #endif /* AVDEVICE_DECKLINK_COMMON_C_H */
diff --git a/libavdevice/decklink_dec.cpp b/libavdevice/decklink_dec.cpp
index bea9213..47323b1 100644
--- a/libavdevice/decklink_dec.cpp
+++ b/libavdevice/decklink_dec.cpp
@@ -670,6 +670,33 @@ error:
     return ret;
 }
 
+static int setup_data(AVFormatContext *avctx)
+{
+    struct decklink_cctx *cctx = (struct decklink_cctx *)avctx->priv_data;
+    struct decklink_ctx *ctx = (struct decklink_ctx *)cctx->ctx;
+    AVStream *st;
+    int ret = 0;
+
+    if (cctx->enable_scte_104) {
+        st = avformat_new_stream(avctx, NULL);
+        if (!st) {
+            av_log(avctx, AV_LOG_ERROR, "Cannot add data stream\n");
+            ret = AVERROR(ENOMEM);
+            goto error;
+        }
+        st->codecpar->codec_type  = AVMEDIA_TYPE_DATA;
+        st->time_base.den         = ctx->bmd_tb_den;
+        st->time_base.num         = ctx->bmd_tb_num;
+        st->codecpar->codec_id    = AV_CODEC_ID_SCTE_104;
+        avpriv_set_pts_info(st, 64, 1, 1000000);  /* 64 bits pts in us */
+        ctx->data_st[ctx->num_data_streams] = st;
+        ctx->num_data_streams++;
+    }
+
+error:
+    return ret;
+}
+
 #if CONFIG_LIBKLVANC
 /* VANC Callbacks */
 struct vanc_cb_ctx {
@@ -735,12 +762,44 @@ static int cb_EIA_708B(void *callback_context, struct klvanc_context_s *ctx,
     return 0;
 }
 
+static int cb_SCTE_104(void *callback_context, struct klvanc_context_s *ctx,
+                       struct klvanc_packet_scte_104_s *pkt)
+{
+    struct vanc_cb_ctx *cb_ctx = (struct vanc_cb_ctx *)callback_context;
+    decklink_cctx *decklink_cctx = (struct decklink_cctx *)cb_ctx->avctx->priv_data;
+    struct decklink_ctx *decklink_ctx = (struct decklink_ctx *)decklink_cctx->ctx;
+    AVPacket avpkt;
+    av_init_packet(&avpkt);
+
+    avpkt.stream_index = -1;
+    for (int i = 0; i < decklink_ctx->num_data_streams; i++) {
+        if (decklink_ctx->data_st[i]->codecpar->codec_id = AV_CODEC_ID_SCTE_104) {
+            avpkt.stream_index = decklink_ctx->data_st[i]->index;
+            break;
+        }
+    }
+    if (avpkt.stream_index == -1) {
+        /* SCTE-104 packet received but forwarding is disabled */
+        return 0;
+    }
+
+    avpkt.pts = cb_ctx->pkt->pts;
+    avpkt.dts = cb_ctx->pkt->dts;
+    avpkt.data = pkt->payload;
+    avpkt.size = pkt->payloadLengthBytes;
+    if (avpacket_queue_put(&decklink_ctx->queue, &avpkt) < 0) {
+        ++decklink_ctx->dropped;
+    }
+
+    return 0;
+}
+
 static struct klvanc_callbacks_s callbacks =
 {
     .afd               = cb_AFD,
     .eia_708b          = cb_EIA_708B,
     .eia_608           = NULL,
-    .scte_104          = NULL,
+    .scte_104          = cb_SCTE_104,
     .all               = NULL,
     .kl_i64le_counter  = NULL,
 };
@@ -1224,6 +1283,9 @@ av_cold int ff_decklink_read_header(AVFormatContext *avctx)
         ctx->teletext_st = st;
     }
 
+    /* Setup streams. */
+    setup_data(avctx);
+
     if (cctx->audio_mode == AUDIO_MODE_DISCRETE) {
         av_log(avctx, AV_LOG_VERBOSE, "Using %d input audio channels\n", ctx->audio_st[0]->codecpar->channels);
         result = ctx->dli->EnableAudioInput(bmdAudioSampleRate48kHz,
diff --git a/libavdevice/decklink_dec_c.c b/libavdevice/decklink_dec_c.c
index d3d8c84..122da08 100644
--- a/libavdevice/decklink_dec_c.c
+++ b/libavdevice/decklink_dec_c.c
@@ -76,6 +76,7 @@ static const AVOption options[] = {
     { "draw_bars",     "draw bars on signal loss" , OFFSET(draw_bars),    AV_OPT_TYPE_BOOL,  { .i64 = 1}, 0, 1, DEC },
     { "queue_size",    "input queue buffer size",   OFFSET(queue_size),   AV_OPT_TYPE_INT64, { .i64 = (1024 * 1024 * 1024)}, 0, INT64_MAX, DEC },
     { "audio_depth",   "audio bitdepth (16 or 32)", OFFSET(audio_depth),  AV_OPT_TYPE_INT,   { .i64 = 16}, 16, 32, DEC },
+    { "enable_scte_104", "capture SCTE-104 VANC", OFFSET(enable_scte_104), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 1, DEC, "enable_scte_104"},
     { NULL },
 };
 
-- 
1.8.3.1



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