v4l2codecs: gstv4l2codecsmpeg2dec: implement a render delay

The v4l2 backend support delayed output for performance reasons.
It is then possible to use render delays to queue multiple requests
simultaneously, thus increasing performance.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/1013>
This commit is contained in:
Daniel Almeida 2021-04-08 16:24:49 -03:00 committed by GStreamer Marge Bot
parent a8decde6d3
commit f9958eda8e

View file

@ -96,6 +96,24 @@ G_DEFINE_ABSTRACT_TYPE_WITH_CODE (GstV4l2CodecMpeg2Dec,
"V4L2 stateless mpeg2 decoder"));
#define parent_class gst_v4l2_codec_mpeg2_dec_parent_class
static guint
gst_v4l2_codec_mpeg2_dec_get_preferred_output_delay (GstMpeg2Decoder * decoder,
gboolean is_live)
{
GstV4l2CodecMpeg2Dec *self = GST_V4L2_CODEC_MPEG2_DEC (decoder);
guint delay;
if (is_live)
delay = 0;
else
/* Just one for now, perhaps we can make this configurable in the future. */
delay = 1;
gst_v4l2_decoder_set_render_delay (self->decoder, delay);
return delay;
}
static gboolean
gst_v4l2_codec_mpeg2_dec_open (GstVideoDecoder * decoder)
{
@ -319,7 +337,8 @@ gst_v4l2_codec_mpeg2_dec_decide_allocation (GstVideoDecoder * decoder,
min = MAX (2, min);
/* note the dpb size is fixed at 2 */
num_bitstream = 2;
num_bitstream = 1 +
MAX (1, gst_v4l2_decoder_get_render_delay (self->decoder));
self->sink_allocator = gst_v4l2_codec_allocator_new (self->decoder,
GST_PAD_SINK, num_bitstream);
@ -1020,6 +1039,8 @@ gst_v4l2_codec_mpeg2_dec_subclass_init (GstV4l2CodecMpeg2DecClass * klass,
GST_DEBUG_FUNCPTR (gst_v4l2_codec_mpeg2_dec_decode_slice);
mpeg2decoder_class->end_picture =
GST_DEBUG_FUNCPTR (gst_v4l2_codec_mpeg2_dec_end_picture);
mpeg2decoder_class->get_preferred_output_delay =
GST_DEBUG_FUNCPTR (gst_v4l2_codec_mpeg2_dec_get_preferred_output_delay);
klass->device = device;
gst_v4l2_decoder_install_properties (gobject_class, PROP_LAST, device);