videodecoder: Add API for subclasses to signal that they need the stream to start with a sync point

If the first frame(s) at the very beginning or after a flush are not a
sync point then the base class would discard them before passing them to
the subclass.

This also fixes the previously broken distance_from_sync handling: it
was never reset at sync points.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-base/-/merge_requests/730>
This commit is contained in:
Sebastian Dröge 2020-07-01 18:14:40 +03:00 committed by GStreamer Merge Bot
parent 1afb145dc5
commit fdf79a786c
2 changed files with 82 additions and 11 deletions

View file

@ -377,10 +377,14 @@ struct _GstVideoDecoderPrivate
/* combine with base_picture_number, framerate and calcs to yield (presentation) ts */
GstClockTime base_timestamp;
int distance_from_sync;
/* Properties */
gboolean discard_corrupted_frames;
/* Key unit related state */
gboolean needs_sync_point;
/* -1 if we saw no sync point yet */
guint64 distance_from_sync;
guint32 system_frame_number;
guint32 decode_frame_number;
@ -2180,6 +2184,7 @@ gst_video_decoder_reset (GstVideoDecoder * decoder, gboolean full,
priv->proportion = 0.5;
priv->decode_flags_override = FALSE;
GST_OBJECT_UNLOCK (decoder);
priv->distance_from_sync = -1;
}
if (full) {
@ -3571,8 +3576,6 @@ gst_video_decoder_decode_frame (GstVideoDecoder * decoder,
* implementation, or it doesn't) */
g_return_val_if_fail (decoder_class->handle_frame != NULL, GST_FLOW_ERROR);
frame->distance_from_sync = priv->distance_from_sync;
priv->distance_from_sync++;
frame->pts = GST_BUFFER_PTS (frame->input_buffer);
frame->dts = GST_BUFFER_DTS (frame->input_buffer);
frame->duration = GST_BUFFER_DURATION (frame->input_buffer);
@ -3582,16 +3585,31 @@ gst_video_decoder_decode_frame (GstVideoDecoder * decoder,
/* FIXME upstream can be quite wrong about the keyframe aspect,
* so we could be going off here as well,
* maybe let subclass decide if it really is/was a keyframe */
if (GST_VIDEO_CODEC_FRAME_IS_SYNC_POINT (frame) &&
GST_CLOCK_TIME_IS_VALID (frame->pts)
&& GST_CLOCK_TIME_IS_VALID (frame->dts)) {
/* just in case they are not equal as might ideally be,
* e.g. quicktime has a (positive) delta approach */
priv->pts_delta = frame->pts - frame->dts;
GST_DEBUG_OBJECT (decoder, "PTS delta %d ms",
(gint) (priv->pts_delta / GST_MSECOND));
if (GST_VIDEO_CODEC_FRAME_IS_SYNC_POINT (frame)) {
priv->distance_from_sync = 0;
if (GST_CLOCK_TIME_IS_VALID (frame->pts)
&& GST_CLOCK_TIME_IS_VALID (frame->dts)) {
/* just in case they are not equal as might ideally be,
* e.g. quicktime has a (positive) delta approach */
priv->pts_delta = frame->pts - frame->dts;
GST_DEBUG_OBJECT (decoder, "PTS delta %d ms",
(gint) (priv->pts_delta / GST_MSECOND));
}
} else {
if (priv->needs_sync_point && priv->distance_from_sync == -1) {
GST_WARNING_OBJECT (decoder,
"Subclass requires a sync point but we didn't receive one yet, discarding input");
GST_OBJECT_UNLOCK (decoder);
gst_video_decoder_release_frame (decoder, frame);
return GST_FLOW_OK;
}
priv->distance_from_sync++;
}
frame->distance_from_sync = priv->distance_from_sync;
frame->abidata.ABI.ts = frame->dts;
frame->abidata.ABI.ts2 = frame->pts;
@ -4683,3 +4701,49 @@ gst_video_decoder_set_use_default_pad_acceptcaps (GstVideoDecoder * decoder,
{
decoder->priv->use_default_pad_acceptcaps = use;
}
/**
* gst_video_decoder_set_needs_sync_point:
* @dec: a #GstVideoDecoder
* @enabled: new state
*
* Configures whether the decoder requires a sync point before it starts
* outputting data in the beginning. If enabled, the base class will discard
* all non-sync point frames in the beginning and after a flush and does not
* pass it to the subclass.
*
* If the first frame is not a sync point, the base class will request a sync
* point via the force-key-unit event.
*
* Since: 1.20
*/
void
gst_video_decoder_set_needs_sync_point (GstVideoDecoder * dec, gboolean enabled)
{
g_return_if_fail (GST_IS_VIDEO_DECODER (dec));
dec->priv->needs_sync_point = enabled;
}
/**
* gst_video_decoder_get_needs_sync_point:
* @dec: a #GstVideoDecoder
*
* Queries if the decoder requires a sync point before it starts outputting
* data in the beginning.
*
* Returns: %TRUE if a sync point is required in the beginning.
*
* Since: 1.20
*/
gboolean
gst_video_decoder_get_needs_sync_point (GstVideoDecoder * dec)
{
gboolean result;
g_return_val_if_fail (GST_IS_VIDEO_DECODER (dec), FALSE);
result = dec->priv->needs_sync_point;
return result;
}

View file

@ -374,6 +374,13 @@ void gst_video_decoder_set_needs_format (GstVideoDecoder * dec,
GST_VIDEO_API
gboolean gst_video_decoder_get_needs_format (GstVideoDecoder * dec);
GST_VIDEO_API
void gst_video_decoder_set_needs_sync_point (GstVideoDecoder * dec,
gboolean enabled);
GST_VIDEO_API
gboolean gst_video_decoder_get_needs_sync_point (GstVideoDecoder * dec);
GST_VIDEO_API
void gst_video_decoder_set_latency (GstVideoDecoder *decoder,
GstClockTime min_latency,