avdevice/decklink_dec: extend available actions on signal loss

Deprecate the option 'draw_bars' in favor of the new option 'signal_loss_action',
which controls the behavior when the input signal is not available
(including the behavior previously available through draw_bars).
The default behavior remains unchanged to be backwards compatible.
The new option is more flexible for extending now and in the future.

The new value 'repeat' repeats the last video frame.
This is useful for very short dropouts and was not available before.

Signed-off-by: Michael Riedl <michael.riedl@nativewaves.com>
Signed-off-by: Marton Balint <cus@passwd.hu>

1 files changed, 29 insertions, 3 deletions

diff --git a/libavdevice/decklink_dec.cpp b/libavdevice/decklink_dec.cpp
index 671573853b..54d698bc12 100644
--- a/libavdevice/decklink_dec.cpp
+++ b/libavdevice/decklink_dec.cpp
@@ -593,6 +593,7 @@ private:
         int no_video;
         int64_t initial_video_pts;
         int64_t initial_audio_pts;
+        IDeckLinkVideoInputFrame* last_video_frame;
 };
 
 decklink_input_callback::decklink_input_callback(AVFormatContext *_avctx) : _refs(1)
@@ -602,10 +603,13 @@ decklink_input_callback::decklink_input_callback(AVFormatContext *_avctx) : _ref
     ctx = (struct decklink_ctx *)cctx->ctx;
     no_video = 0;
     initial_audio_pts = initial_video_pts = AV_NOPTS_VALUE;
+    last_video_frame = nullptr;
 }
 
 decklink_input_callback::~decklink_input_callback()
 {
+    if (last_video_frame)
+        last_video_frame->Release();
 }
 
 ULONG decklink_input_callback::AddRef(void)
@@ -729,6 +733,7 @@ HRESULT decklink_input_callback::VideoInputFrameArrived(
     BMDTimeValue frameTime;
     BMDTimeValue frameDuration;
     int64_t wallclock = 0, abs_wallclock = 0;
+    int64_t video_pkt_pts, audio_pkt_pts;
     struct decklink_cctx *cctx = (struct decklink_cctx *) avctx->priv_data;
 
     if (ctx->autodetect) {
@@ -755,6 +760,8 @@ HRESULT decklink_input_callback::VideoInputFrameArrived(
         wallclock = av_gettime_relative();
     if (ctx->audio_pts_source == PTS_SRC_ABS_WALLCLOCK || ctx->video_pts_source == PTS_SRC_ABS_WALLCLOCK)
         abs_wallclock = av_gettime();
+    video_pkt_pts = get_pkt_pts(videoFrame, audioFrame, wallclock, abs_wallclock, ctx->video_pts_source, ctx->video_st->time_base, &initial_video_pts, cctx->copyts);
+    audio_pkt_pts = get_pkt_pts(videoFrame, audioFrame, wallclock, abs_wallclock, ctx->audio_pts_source, ctx->audio_st->time_base, &initial_audio_pts, cctx->copyts);
 
     // Handle Video Frame
     if (videoFrame) {
@@ -773,7 +780,7 @@ HRESULT decklink_input_callback::VideoInputFrameArrived(
                                   ctx->video_st->time_base.den);
 
         if (videoFrame->GetFlags() & bmdFrameHasNoInputSource) {
-            if (ctx->draw_bars && videoFrame->GetPixelFormat() == bmdFormat8BitYUV) {
+            if (ctx->signal_loss_action == SIGNAL_LOSS_BARS && videoFrame->GetPixelFormat() == bmdFormat8BitYUV) {
                 unsigned bars[8] = {
                     0xEA80EA80, 0xD292D210, 0xA910A9A5, 0x90229035,
                     0x6ADD6ACA, 0x51EF515A, 0x286D28EF, 0x10801080 };
@@ -785,6 +792,9 @@ HRESULT decklink_input_callback::VideoInputFrameArrived(
                     for (int x = 0; x < width; x += 2)
                         *p++ = bars[(x * 8) / width];
                 }
+            } else if (ctx->signal_loss_action == SIGNAL_LOSS_REPEAT && last_video_frame) {
+                videoFrame = last_video_frame;
+                videoFrame->GetBytes(&frameBytes);
             }
 
             if (!no_video) {
@@ -793,6 +803,12 @@ HRESULT decklink_input_callback::VideoInputFrameArrived(
             }
             no_video = 1;
         } else {
+            if (ctx->signal_loss_action == SIGNAL_LOSS_REPEAT) {
+                if (last_video_frame)
+                    last_video_frame->Release();
+                last_video_frame = videoFrame;
+                last_video_frame->AddRef();
+            }
             if (no_video) {
                 av_log(avctx, AV_LOG_WARNING, "Frame received (#%lu) - Input returned "
                         "- Frames dropped %u\n", ctx->frameCount, ++ctx->dropped);
@@ -846,7 +862,7 @@ HRESULT decklink_input_callback::VideoInputFrameArrived(
             return S_OK;
         }
 
-        pkt.pts = get_pkt_pts(videoFrame, audioFrame, wallclock, abs_wallclock, ctx->video_pts_source, ctx->video_st->time_base, &initial_video_pts, cctx->copyts);
+        pkt.pts = video_pkt_pts;
         pkt.dts = pkt.pts;
 
         pkt.duration = frameDuration;
@@ -949,7 +965,7 @@ HRESULT decklink_input_callback::VideoInputFrameArrived(
         pkt.size = audioFrame->GetSampleFrameCount() * ctx->audio_st->codecpar->ch_layout.nb_channels * (ctx->audio_depth / 8);
         audioFrame->GetBytes(&audioFrameBytes);
         audioFrame->GetPacketTime(&audio_pts, ctx->audio_st->time_base.den);
-        pkt.pts = get_pkt_pts(videoFrame, audioFrame, wallclock, abs_wallclock, ctx->audio_pts_source, ctx->audio_st->time_base, &initial_audio_pts, cctx->copyts);
+        pkt.pts = audio_pkt_pts;
         pkt.dts = pkt.pts;
 
         //fprintf(stderr,"Audio Frame size %d ts %d\n", pkt.size, pkt.pts);
@@ -1036,6 +1052,7 @@ av_cold int ff_decklink_read_close(AVFormatContext *avctx)
         ctx->dli->StopStreams();
         ctx->dli->DisableVideoInput();
         ctx->dli->DisableAudioInput();
+        ctx->dli->SetCallback(nullptr);
     }
 
     ff_decklink_cleanup(avctx);
@@ -1074,6 +1091,15 @@ av_cold int ff_decklink_read_header(AVFormatContext *avctx)
     ctx->audio_pts_source = cctx->audio_pts_source;
     ctx->video_pts_source = cctx->video_pts_source;
     ctx->draw_bars = cctx->draw_bars;
+    ctx->signal_loss_action = cctx->signal_loss_action;
+    if (!ctx->draw_bars && ctx->signal_loss_action == SIGNAL_LOSS_BARS) {
+        ctx->signal_loss_action = SIGNAL_LOSS_NONE;
+        av_log(avctx, AV_LOG_WARNING, "Setting signal_loss_action to none because draw_bars is false\n");
+    }
+    if (!ctx->draw_bars && ctx->signal_loss_action != SIGNAL_LOSS_NONE) {
+        av_log(avctx, AV_LOG_ERROR, "options draw_bars and signal_loss_action are mutually exclusive\n");
+        return AVERROR(EINVAL);
+    }
     ctx->audio_depth = cctx->audio_depth;
     if (cctx->raw_format > 0 && (unsigned int)cctx->raw_format < FF_ARRAY_ELEMS(decklink_raw_format_map))
         ctx->raw_format = decklink_raw_format_map[cctx->raw_format];