diff options
| -rw-r--r-- | doc/indevs.texi | 14 | ||||
| -rw-r--r-- | libavdevice/decklink_common_c.h | 1 | ||||
| -rw-r--r-- | libavdevice/decklink_dec.cpp | 10 | ||||
| -rw-r--r-- | libavdevice/decklink_dec_c.c | 1 | ||||
| -rw-r--r-- | libavdevice/version.h | 2 |
5 files changed, 27 insertions, 1 deletions
diff --git a/doc/indevs.texi b/doc/indevs.texi index ed2784b..9a9cb69 100644 --- a/doc/indevs.texi +++ b/doc/indevs.texi @@ -371,6 +371,20 @@ If set to @option{true}, timestamps are forwarded as they are without removing the initial offset. Defaults to @option{false}. +@item timestamp_align +Capture start time alignment in seconds. If set to nonzero, input frames are +dropped till the system timestamp aligns with configured value. +Alignment difference of upto one frame duration is tolerated. +This is useful for maintaining input synchronization across N different +hardware devices deployed for 'N-way' redundancy. The system time of different +hardware devices should be synchronized with protocols such as NTP or PTP, +before using this option. +Note that this method is not foolproof. In some border cases input +synchronization may not happen due to thread scheduling jitters in the OS. +Either sync could go wrong by 1 frame or in a rarer case +@option{timestamp_align} seconds. +Defaults to @samp{0}. + @end table @subsection Examples diff --git a/libavdevice/decklink_common_c.h b/libavdevice/decklink_common_c.h index 32a5d70..8e3bbeb 100644 --- a/libavdevice/decklink_common_c.h +++ b/libavdevice/decklink_common_c.h @@ -56,6 +56,7 @@ struct decklink_cctx { int raw_format; int64_t queue_size; int copyts; + int64_t timestamp_align; }; #endif /* AVDEVICE_DECKLINK_COMMON_C_H */ diff --git a/libavdevice/decklink_dec.cpp b/libavdevice/decklink_dec.cpp index 7fabef2..deb8f78 100644 --- a/libavdevice/decklink_dec.cpp +++ b/libavdevice/decklink_dec.cpp @@ -703,6 +703,16 @@ HRESULT decklink_input_callback::VideoInputFrameArrived( return S_OK; } + // Drop the frames till system's timestamp aligns with the configured value. + if (0 == ctx->frameCount && cctx->timestamp_align) { + AVRational remainder = av_make_q(av_gettime() % cctx->timestamp_align, 1000000); + AVRational frame_duration = av_inv_q(ctx->video_st->r_frame_rate); + if (av_cmp_q(remainder, frame_duration) > 0) { + ++ctx->dropped; + return S_OK; + } + } + ctx->frameCount++; if (ctx->audio_pts_source == PTS_SRC_WALLCLOCK || ctx->video_pts_source == PTS_SRC_WALLCLOCK) wallclock = av_gettime_relative(); diff --git a/libavdevice/decklink_dec_c.c b/libavdevice/decklink_dec_c.c index 6ab3819..91d2839 100644 --- a/libavdevice/decklink_dec_c.c +++ b/libavdevice/decklink_dec_c.c @@ -84,6 +84,7 @@ static const AVOption options[] = { { "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 }, { NULL }, }; diff --git a/libavdevice/version.h b/libavdevice/version.h index 8c96e60..e6ee009 100644 --- a/libavdevice/version.h +++ b/libavdevice/version.h @@ -29,7 +29,7 @@ #define LIBAVDEVICE_VERSION_MAJOR 58 #define LIBAVDEVICE_VERSION_MINOR 4 -#define LIBAVDEVICE_VERSION_MICRO 104 +#define LIBAVDEVICE_VERSION_MICRO 105 #define LIBAVDEVICE_VERSION_INT AV_VERSION_INT(LIBAVDEVICE_VERSION_MAJOR, \ LIBAVDEVICE_VERSION_MINOR, \ |
