[FFmpeg-devel] [PATCH v2 1/1] libavdevice/decklink: extend available actions on signal loss
Marton Balint
cus at passwd.hu
Wed May 8 01:47:28 EEST 2024
On Tue, 23 Apr 2024, Michael Riedl wrote:
> 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.
As far as I see, you are overriding frameBytes for a repeated frame,
that seems wrong. pkt.data (frameBytes) must be associated with the
videoFrame which is passed to av_buffer_create() later on.
Every AVFrame returned by the decklink device has an AVBuffer set up which
keeps a reference to the original DeckLink frame. This allows the use
of the DeckLink frame's raw buffer directly. But you cannot use the raw
buffer of another DeckLink frame for which the AVBuffer of the AVFrame
does not keep a reference.
Regards,
Marton
>
> Signed-off-by: Michael Riedl <michael.riedl at nativewaves.com>
> ---
> doc/indevs.texi | 16 ++++++++++++++++
> libavdevice/decklink_common.h | 1 +
> libavdevice/decklink_common_c.h | 7 +++++++
> libavdevice/decklink_dec.cpp | 23 ++++++++++++++++++++++-
> libavdevice/decklink_dec_c.c | 6 +++++-
> 5 files changed, 51 insertions(+), 2 deletions(-)
>
> diff --git a/doc/indevs.texi b/doc/indevs.texi
> index 734fc657523..cdf44a66382 100644
> --- a/doc/indevs.texi
> +++ b/doc/indevs.texi
> @@ -396,6 +396,22 @@ Defaults to @samp{audio}.
> @item draw_bars
> If set to @samp{true}, color bars are drawn in the event of a signal loss.
> Defaults to @samp{true}.
> +This option is deprecated, please use the @code{signal_loss_action} option.
> +
> + at item signal_loss_action
> +Sets the action to take in the event of a signal loss. Accepts one of the
> +following values:
> +
> + at table @option
> + at item 1, none
> +Do nothing on signal loss. This usually results in black frames.
> + at item 2, bars
> +Draw color bars on signal loss. Only supported for 8-bit input signals.
> + at item 3, repeat
> +Repeat the last video frame on signal loss.
> + at end table
> +
> +Defaults to @samp{bars}.
>
> @item queue_size
> Sets maximum input buffer size in bytes. If the buffering reaches this value,
> diff --git a/libavdevice/decklink_common.h b/libavdevice/decklink_common.h
> index c54a635876c..6b32dc2d09c 100644
> --- a/libavdevice/decklink_common.h
> +++ b/libavdevice/decklink_common.h
> @@ -147,6 +147,7 @@ struct decklink_ctx {
> DecklinkPtsSource video_pts_source;
> int draw_bars;
> BMDPixelFormat raw_format;
> + DecklinkSignalLossAction signal_loss_action;
>
> int frames_preroll;
> int frames_buffer;
> diff --git a/libavdevice/decklink_common_c.h b/libavdevice/decklink_common_c.h
> index 9c55d891494..53d2c583e7e 100644
> --- a/libavdevice/decklink_common_c.h
> +++ b/libavdevice/decklink_common_c.h
> @@ -37,6 +37,12 @@ typedef enum DecklinkPtsSource {
> PTS_SRC_NB
> } DecklinkPtsSource;
>
> +typedef enum DecklinkSignalLossAction {
> + SIGNAL_LOSS_NONE = 1,
> + SIGNAL_LOSS_REPEAT = 2,
> + SIGNAL_LOSS_BARS = 3
> +} DecklinkSignalLossAction;
> +
> struct decklink_cctx {
> const AVClass *cclass;
>
> @@ -68,6 +74,7 @@ struct decklink_cctx {
> int64_t timestamp_align;
> int timing_offset;
> int wait_for_tc;
> + DecklinkSignalLossAction signal_loss_action;
> };
>
> #endif /* AVDEVICE_DECKLINK_COMMON_C_H */
> diff --git a/libavdevice/decklink_dec.cpp b/libavdevice/decklink_dec.cpp
> index 671573853ba..1c2d08ea9fc 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)
> @@ -773,7 +777,7 @@ 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 +789,8 @@ 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->GetBytes(&frameBytes);
> }
>
> if (!no_video) {
> @@ -793,6 +799,12 @@ 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);
> @@ -1074,6 +1086,15 @@ 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];
> diff --git a/libavdevice/decklink_dec_c.c b/libavdevice/decklink_dec_c.c
> index e211c9d3f4e..b8cdb7bd8e1 100644
> --- a/libavdevice/decklink_dec_c.c
> +++ b/libavdevice/decklink_dec_c.c
> @@ -95,12 +95,16 @@ static const AVOption options[] = {
> { "reference", NULL, 0, AV_OPT_TYPE_CONST, { .i64 = PTS_SRC_REFERENCE}, 0, 0, DEC, .unit = "pts_source"},
> { "wallclock", NULL, 0, AV_OPT_TYPE_CONST, { .i64 = PTS_SRC_WALLCLOCK}, 0, 0, DEC, .unit = "pts_source"},
> { "abs_wallclock", NULL, 0, AV_OPT_TYPE_CONST, { .i64 = PTS_SRC_ABS_WALLCLOCK}, 0, 0, DEC, .unit = "pts_source"},
> - { "draw_bars", "draw bars on signal loss" , OFFSET(draw_bars), AV_OPT_TYPE_BOOL, { .i64 = 1}, 0, 1, DEC },
> + { "draw_bars", "use option signal_loss_action instead" , OFFSET(draw_bars), AV_OPT_TYPE_BOOL, { .i64 = 1}, 0, 1, DEC | AV_OPT_FLAG_DEPRECATED },
> { "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 },
> { "decklink_copyts", "copy timestamps, do not remove the initial offset", OFFSET(copyts), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, DEC },
> { "timestamp_align", "capture start time alignment (in seconds)", OFFSET(timestamp_align), AV_OPT_TYPE_DURATION, { .i64 = 0 }, 0, INT_MAX, DEC },
> { "wait_for_tc", "drop frames till a frame with timecode is received. TC format must be set", OFFSET(wait_for_tc), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, DEC },
> + { "signal_loss_action", "action on signal loss", OFFSET(signal_loss_action), AV_OPT_TYPE_INT, { .i64 = SIGNAL_LOSS_BARS }, SIGNAL_LOSS_NONE, SIGNAL_LOSS_BARS, DEC, .unit = "signal_loss_action" },
> + { "none", "do not do anything (usually leads to black frames)", 0, AV_OPT_TYPE_CONST, { .i64 = SIGNAL_LOSS_NONE }, 0, 0, DEC, .unit = "signal_loss_action"},
> + { "bars", "draw color bars (only supported for 8-bit signals)", 0, AV_OPT_TYPE_CONST, { .i64 = SIGNAL_LOSS_BARS }, 0, 0, DEC, .unit = "signal_loss_action"},
> + { "repeat", "repeat the last video frame", 0, AV_OPT_TYPE_CONST, { .i64 = SIGNAL_LOSS_REPEAT }, 0, 0, DEC, .unit = "signal_loss_action"},
> { NULL },
> };
>
> --
> 2.43.0
>
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