From 7dc33aad45772ca3c0a3092833cf8447d1607663 Mon Sep 17 00:00:00 2001 From: Diederick Niehorster Date: Tue, 21 Dec 2021 14:53:27 +0100 Subject: [PATCH] avdevice/dshow: implement option to use device video timestamps The dshow avdevice ignores timestamps for video frames provided by the DirectShow device, instead using wallclock time, apparently because the implementer of this code had a device that provided unreliable timestamps. Me (and others) would like to use the device's timestamps. The new use_video_device_timestamps option for dshow device enables them to do so. Since the majority of video devices out there probably provide fine timestamps, this patch sets the default to using the device timestamps, which means best fidelity timestamps are used by default. Using the new option, the user can switch this off and revert to the old behavior, so a fall back remains available in case the device provides broken timestamps. add use_video_device_timestamps to docs. Closes: #8620 Signed-off-by: Diederick Niehorster Reviewed-by: Roger Pack --- doc/indevs.texi | 6 ++++++ libavdevice/dshow.c | 1 + libavdevice/dshow_capture.h | 1 + libavdevice/dshow_pin.c | 11 ++++++----- 4 files changed, 14 insertions(+), 5 deletions(-) diff --git a/doc/indevs.texi b/doc/indevs.texi index 5be647f70aa73..9d8020311aeba 100644 --- a/doc/indevs.texi +++ b/doc/indevs.texi @@ -625,6 +625,12 @@ Save the currently used video capture filter device and its parameters (if the filter supports it) to a file. If a file with the same name exists it will be overwritten. +@item use_video_device_timestamps +If set to @option{false}, the timestamp for video frames will be +derived from the wallclock instead of the timestamp provided by +the capture device. This allows working around devices that +provide unreliable timestamps. + @end table @subsection Examples diff --git a/libavdevice/dshow.c b/libavdevice/dshow.c index cc0bef0474400..5e6eb9c85d673 100644 --- a/libavdevice/dshow.c +++ b/libavdevice/dshow.c @@ -1310,6 +1310,7 @@ static const AVOption options[] = { { "audio_device_save", "save audio capture filter device (and properties) to file", OFFSET(audio_filter_save_file), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, DEC }, { "video_device_load", "load video capture filter device (and properties) from file", OFFSET(video_filter_load_file), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, DEC }, { "video_device_save", "save video capture filter device (and properties) to file", OFFSET(video_filter_save_file), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, DEC }, + { "use_video_device_timestamps", "use device instead of wallclock timestamps for video frames", OFFSET(use_video_device_timestamps), AV_OPT_TYPE_BOOL, {.i64 = 1}, 0, 1, DEC }, { NULL }, }; diff --git a/libavdevice/dshow_capture.h b/libavdevice/dshow_capture.h index 06ded2ba96786..5a2691518ce22 100644 --- a/libavdevice/dshow_capture.h +++ b/libavdevice/dshow_capture.h @@ -312,6 +312,7 @@ struct dshow_ctx { char *audio_filter_save_file; char *video_filter_load_file; char *video_filter_save_file; + int use_video_device_timestamps; IBaseFilter *device_filter[2]; IPin *device_pin[2]; diff --git a/libavdevice/dshow_pin.c b/libavdevice/dshow_pin.c index 3dae405e652ad..8e56dccbfef8f 100644 --- a/libavdevice/dshow_pin.c +++ b/libavdevice/dshow_pin.c @@ -309,10 +309,14 @@ long ff_dshow_meminputpin_Receive(DShowMemInputPin *this, IMediaSample *sample) if (!sample) return E_POINTER; + priv_data = pin->filter->priv_data; + s = priv_data; + ctx = s->priv_data; + IMediaSample_GetTime(sample, &orig_curtime, &dummy); orig_curtime += pin->filter->start_time; IReferenceClock_GetTime(clock, &graphtime); - if (devtype == VideoDevice) { + if (devtype == VideoDevice && !ctx->use_video_device_timestamps) { /* PTS from video devices is unreliable. */ IReferenceClock_GetTime(clock, &curtime); } else { @@ -322,7 +326,7 @@ long ff_dshow_meminputpin_Receive(DShowMemInputPin *this, IMediaSample *sample) like 437650244077016960 which FFmpeg doesn't like. TODO figure out math. For now just drop them. */ av_log(NULL, AV_LOG_DEBUG, - "dshow dropping initial (or ending) audio frame with odd PTS too high %"PRId64"\n", curtime); + "dshow dropping initial (or ending) frame with odd PTS too high %"PRId64"\n", curtime); return S_OK; } curtime += pin->filter->start_time; @@ -330,9 +334,6 @@ long ff_dshow_meminputpin_Receive(DShowMemInputPin *this, IMediaSample *sample) buf_size = IMediaSample_GetActualDataLength(sample); IMediaSample_GetPointer(sample, &buf); - priv_data = pin->filter->priv_data; - s = priv_data; - ctx = s->priv_data; index = pin->filter->stream_index; av_log(NULL, AV_LOG_VERBOSE, "dshow passing through packet of type %s size %8d "