From ff373bb4a87a5b17dfa82aba5c7e74b125298fa8 Mon Sep 17 00:00:00 2001
From: Marton Balint <cus@passwd.hu>
Date: Sat, 5 Sep 2020 23:29:24 +0200
Subject: [PATCH] avdevice/decklink_dec: add support for 50/60 fps timecode

Signed-off-by: Marton Balint <cus@passwd.hu>
---
 doc/indevs.texi              |  5 +++
 libavdevice/decklink_dec.cpp | 64 +++++++++++++++++++++++++++++-------
 2 files changed, 57 insertions(+), 12 deletions(-)

diff --git a/doc/indevs.texi b/doc/indevs.texi
index 62b6ebb3e3..3924d03908 100644
--- a/doc/indevs.texi
+++ b/doc/indevs.texi
@@ -353,6 +353,11 @@ Timecode type to include in the frame and video stream metadata. Must be
 @samp{rp188hfr}, @samp{rp188any}, @samp{vitc}, @samp{vitc2}, or @samp{serial}.
 Defaults to @samp{none} (not included).
 
+In order to properly support 50/60 fps timecodes, the ordering of the queried
+timecode types for @samp{rp188any} is HFR, VITC1, VITC2 and LTC for >30 fps
+content. Note that this is slightly different to the ordering used by the
+DeckLink API, which is HFR, VITC1, LTC, VITC2.
+
 @item video_input
 Sets the video input source. Must be @samp{unset}, @samp{sdi}, @samp{hdmi},
 @samp{optical_sdi}, @samp{component}, @samp{composite} or @samp{s_video}.
diff --git a/libavdevice/decklink_dec.cpp b/libavdevice/decklink_dec.cpp
index 2e41b587e8..090437a6b5 100644
--- a/libavdevice/decklink_dec.cpp
+++ b/libavdevice/decklink_dec.cpp
@@ -789,6 +789,52 @@ static int64_t get_pkt_pts(IDeckLinkVideoInputFrame *videoFrame,
     return pts;
 }
 
+int get_bmd_timecode(AVFormatContext *avctx, AVTimecode *tc, AVRational frame_rate, BMDTimecodeFormat tc_format, IDeckLinkVideoInputFrame *videoFrame)
+{
+    IDeckLinkTimecode *timecode;
+    int ret = AVERROR(ENOENT);
+#if BLACKMAGIC_DECKLINK_API_VERSION >= 0x0b000000
+    int hfr = (tc_format == bmdTimecodeRP188HighFrameRate);
+#else
+    int hfr = 0;
+#endif
+    if (videoFrame->GetTimecode(tc_format, &timecode) == S_OK) {
+        uint8_t hh, mm, ss, ff;
+        if (timecode->GetComponents(&hh, &mm, &ss, &ff) == S_OK) {
+            int flags = (timecode->GetFlags() & bmdTimecodeIsDropFrame) ? AV_TIMECODE_FLAG_DROPFRAME : 0;
+            if (!hfr && av_cmp_q(frame_rate, av_make_q(30, 1)) == 1)
+                ff = ff << 1 | !!(timecode->GetFlags() & bmdTimecodeFieldMark);
+            ret = av_timecode_init_from_components(tc, frame_rate, flags, hh, mm, ss, ff, avctx);
+        }
+        timecode->Release();
+    }
+    return ret;
+}
+
+int get_frame_timecode(AVFormatContext *avctx, decklink_ctx *ctx, AVTimecode *tc, IDeckLinkVideoInputFrame *videoFrame)
+{
+    AVRational frame_rate = ctx->video_st->r_frame_rate;
+    int ret;
+    /* 50/60 fps content has alternating VITC1 and VITC2 timecode (see SMPTE ST
+     * 12-2, section 7), so the native ordering of RP188Any (HFR, VITC1, LTC,
+     * VITC2) would not work because LTC might not contain the field flag.
+     * Therefore we query the types manually. */
+    if (ctx->tc_format == bmdTimecodeRP188Any && av_cmp_q(frame_rate, av_make_q(30, 1)) == 1) {
+#if BLACKMAGIC_DECKLINK_API_VERSION >= 0x0b000000
+       ret = get_bmd_timecode(avctx, tc, frame_rate, bmdTimecodeRP188HighFrameRate, videoFrame);
+       if (ret == AVERROR(ENOENT))
+#endif
+           ret = get_bmd_timecode(avctx, tc, frame_rate, bmdTimecodeRP188VITC1, videoFrame);
+       if (ret == AVERROR(ENOENT))
+           ret = get_bmd_timecode(avctx, tc, frame_rate, bmdTimecodeRP188VITC2, videoFrame);
+       if (ret == AVERROR(ENOENT))
+           ret = get_bmd_timecode(avctx, tc, frame_rate, bmdTimecodeRP188LTC, videoFrame);
+    } else {
+       ret = get_bmd_timecode(avctx, tc, frame_rate, ctx->tc_format, videoFrame);
+    }
+    return ret;
+}
+
 HRESULT decklink_input_callback::VideoInputFrameArrived(
     IDeckLinkVideoInputFrame *videoFrame, IDeckLinkAudioInputPacket *audioFrame)
 {
@@ -870,22 +916,16 @@ HRESULT decklink_input_callback::VideoInputFrameArrived(
 
             // Handle Timecode (if requested)
             if (ctx->tc_format) {
-                IDeckLinkTimecode *timecode;
-                if (videoFrame->GetTimecode(ctx->tc_format, &timecode) == S_OK) {
-                    const char *tc = NULL;
-                    DECKLINK_STR decklink_tc;
-                    if (timecode->GetString(&decklink_tc) == S_OK) {
-                        tc = DECKLINK_STRDUP(decklink_tc);
-                        DECKLINK_FREE(decklink_tc);
-                    }
-                    timecode->Release();
+                AVTimecode tcr;
+                if (get_frame_timecode(avctx, ctx, &tcr, videoFrame) >= 0) {
+                    char tcstr[AV_TIMECODE_STR_SIZE];
+                    const char *tc = av_timecode_make_string(&tcr, tcstr, 0);
                     if (tc) {
                         AVDictionary* metadata_dict = NULL;
                         int metadata_len;
                         uint8_t* packed_metadata;
-                        AVTimecode tcr;
 
-                        if (av_timecode_init_from_string(&tcr, ctx->video_st->r_frame_rate, tc, ctx) >= 0) {
+                        if (av_cmp_q(ctx->video_st->r_frame_rate, av_make_q(60, 1)) < 1) {
                             uint32_t tc_data = av_timecode_get_smpte_from_framenum(&tcr, 0);
                             int size = sizeof(uint32_t) * 4;
                             uint32_t *sd = (uint32_t *)av_packet_new_side_data(&pkt, AV_PKT_DATA_S12M_TIMECODE, size);
@@ -896,7 +936,7 @@ HRESULT decklink_input_callback::VideoInputFrameArrived(
                             }
                         }
 
-                        if (av_dict_set(&metadata_dict, "timecode", tc, AV_DICT_DONT_STRDUP_VAL) >= 0) {
+                        if (av_dict_set(&metadata_dict, "timecode", tc, 0) >= 0) {
                             packed_metadata = av_packet_pack_dictionary(metadata_dict, &metadata_len);
                             av_dict_free(&metadata_dict);
                             if (packed_metadata) {