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applemedia/avsamplesink: utilise a pull based approach of displaying video frames

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Using requestMediaDataWhenReadyOnQueue the layer will execute a block
when it would like more frames. Using this we can provide the current
frame and avoid needlessly filling the layer's buffer queue causing
older frames to be displayed when under resource pressure.
This commit is contained in:
Matthew Waters 2015-03-04 14:38:36 +11:00
parent eff94f929d
commit 0593480381
2 changed files with 118 additions and 41 deletions
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6
sys/applemedia/avsamplevideosink.h
View file

@ -57,6 +57,12 @@ struct _GstAVSampleVideoSink
gboolean keep_aspect_ratio;
GstBufferPool *pool;
gboolean layer_requesting_data;
GMutex render_lock;
GstBuffer *buffer;
GstFlowReturn render_flow_return;
};
struct _GstAVSampleVideoSinkClass

141
sys/applemedia/avsamplevideosink.m
View file

@ -127,6 +127,8 @@ static void
gst_av_sample_video_sink_init (GstAVSampleVideoSink * av_sink)
{
av_sink->keep_aspect_ratio = TRUE;
g_mutex_init (&av_sink->render_lock);
}
static void
@ -162,6 +164,8 @@ gst_av_sample_video_sink_finalize (GObject * object)
});
}
g_mutex_clear (&av_sink->render_lock);
G_OBJECT_CLASS (parent_class)->finalize (object);
}
@ -214,6 +218,17 @@ gst_av_sample_video_sink_start (GstBaseSink * bsink)
return TRUE;
}
/* with render lock */
static void
_stop_requesting_data (GstAVSampleVideoSink * av_sink)
{
if (av_sink->layer) {
if (av_sink->layer_requesting_data)
[av_sink->layer stopRequestingMediaData];
av_sink->layer_requesting_data = FALSE;
}
}
static gboolean
gst_av_sample_video_sink_stop (GstBaseSink * bsink)
{
@ -225,9 +240,10 @@ gst_av_sample_video_sink_stop (GstBaseSink * bsink)
}
if (av_sink->layer) {
dispatch_async (dispatch_get_main_queue (), ^{
g_mutex_lock (&av_sink->render_lock);
_stop_requesting_data (av_sink);
g_mutex_unlock (&av_sink->render_lock);
[av_sink->layer flushAndRemoveImage];
});
}
return TRUE;
@ -479,23 +495,6 @@ gst_av_sample_video_sink_set_caps (GstBaseSink * bsink, GstCaps * caps)
return TRUE;
}
static GstFlowReturn
gst_av_sample_video_sink_prepare (GstBaseSink * bsink, GstBuffer * buf)
{
GstAVSampleVideoSink *av_sink;
av_sink = GST_AV_SAMPLE_VIDEO_SINK (bsink);
GST_LOG_OBJECT (bsink, "preparing buffer:%p", buf);
if (GST_VIDEO_SINK_WIDTH (av_sink) < 1 ||
GST_VIDEO_SINK_HEIGHT (av_sink) < 1) {
return GST_FLOW_NOT_NEGOTIATED;
}
return GST_FLOW_OK;
}
static void
_unmap_planar_frame (GstVideoFrame * v_frame, const void * data, gsize dataSize,
gsize numberOfPlanes, const void *planeAddressed[])
@ -515,10 +514,10 @@ _unmap_frame (GstVideoFrame * v_frame, const void * data)
g_free (v_frame);
}
static GstFlowReturn
gst_av_sample_video_sink_show_frame (GstVideoSink * vsink, GstBuffer * buf)
/* with render lock */
static gboolean
_enqueue_sample (GstAVSampleVideoSink * av_sink, GstBuffer *buf)
{
GstAVSampleVideoSink *av_sink;
CVPixelBufferRef pbuf;
CMVideoFormatDescriptionRef v_format_desc;
GstVideoFrame *v_frame;
@ -528,11 +527,7 @@ gst_av_sample_video_sink_show_frame (GstVideoSink * vsink, GstBuffer * buf)
gsize l, r, t, b;
gint i;
GST_TRACE_OBJECT (vsink, "rendering buffer:%p", buf);
av_sink = GST_AV_SAMPLE_VIDEO_SINK (vsink);
GST_TRACE_OBJECT (vsink, "redisplay of size:%ux%u, window size:%ux%u",
GST_TRACE_OBJECT (av_sink, "redisplay of size:%ux%u, window size:%ux%u",
GST_VIDEO_INFO_WIDTH (&av_sink->info),
GST_VIDEO_INFO_HEIGHT (&av_sink->info),
GST_VIDEO_SINK_WIDTH (av_sink),
@ -543,7 +538,7 @@ gst_av_sample_video_sink_show_frame (GstVideoSink * vsink, GstBuffer * buf)
if (!gst_video_frame_map (v_frame, &av_sink->info, buf, GST_MAP_READ)) {
GST_ERROR_OBJECT (av_sink, "Failed to map input video frame");
g_free (v_frame);
return GST_FLOW_ERROR;
return FALSE;
}
if (GST_VIDEO_INFO_N_PLANES (&v_frame->info) == 1) {
@ -558,7 +553,7 @@ gst_av_sample_video_sink_show_frame (GstVideoSink * vsink, GstBuffer * buf)
GST_ERROR_OBJECT (av_sink, "Error creating Core Video pixel buffer");
gst_video_frame_unmap (v_frame);
g_free (v_frame);
return GST_FLOW_ERROR;
return FALSE;
}
} else {
/* multi-planar */
@ -587,7 +582,7 @@ gst_av_sample_video_sink_show_frame (GstVideoSink * vsink, GstBuffer * buf)
GST_ERROR_OBJECT (av_sink, "Error creating Core Video pixel buffer");
gst_video_frame_unmap (v_frame);
g_free (v_frame);
return GST_FLOW_ERROR;
return FALSE;
}
}
@ -640,7 +635,7 @@ gst_av_sample_video_sink_show_frame (GstVideoSink * vsink, GstBuffer * buf)
GST_ERROR_OBJECT (av_sink, "Failed to retreive video format from "
"pixel buffer");
CFRelease (pbuf);
return GST_FLOW_ERROR;
return FALSE;
}
sample_time.duration = CMTimeMake (GST_BUFFER_DURATION (buf), GST_SECOND);
@ -653,7 +648,7 @@ gst_av_sample_video_sink_show_frame (GstVideoSink * vsink, GstBuffer * buf)
"CVImageBuffer");
CFRelease (v_format_desc);
CFRelease (pbuf);
return GST_FLOW_ERROR;
return FALSE;
}
CFRelease (v_format_desc);
@ -666,24 +661,100 @@ gst_av_sample_video_sink_show_frame (GstVideoSink * vsink, GstBuffer * buf)
kCFBooleanTrue);
}
dispatch_sync (dispatch_get_main_queue (), ^{
if (av_sink->keep_aspect_ratio)
av_sink->layer.videoGravity = AVLayerVideoGravityResizeAspect;
else
av_sink->layer.videoGravity = AVLayerVideoGravityResize;
[av_sink->layer enqueueSampleBuffer:sample_buf];
});
CFRelease (pbuf);
CFRelease (sample_buf);
return TRUE;
}
static void
_request_data (GstAVSampleVideoSink * av_sink)
{
av_sink->layer_requesting_data = TRUE;
[av_sink->layer requestMediaDataWhenReadyOnQueue:
dispatch_get_global_queue (DISPATCH_QUEUE_PRIORITY_DEFAULT, 0)
usingBlock:^{
while (TRUE) {
/* don't needlessly fill up avsamplebufferdisplaylayer's queue.
* This also allows us to skip displaying late frames */
if (!av_sink->layer.readyForMoreMediaData)
break;
g_mutex_lock (&av_sink->render_lock);
if (!av_sink->buffer || av_sink->render_flow_return != GST_FLOW_OK) {
_stop_requesting_data (av_sink);
g_mutex_unlock (&av_sink->render_lock);
break;
}
if (!_enqueue_sample (av_sink, av_sink->buffer)) {
gst_buffer_unref (av_sink->buffer);
av_sink->buffer = NULL;
av_sink->render_flow_return = GST_FLOW_ERROR;
g_mutex_unlock (&av_sink->render_lock);
break;
}
gst_buffer_unref (av_sink->buffer);
av_sink->buffer = NULL;
av_sink->render_flow_return = GST_FLOW_OK;
g_mutex_unlock (&av_sink->render_lock);
}
}];
}
static GstFlowReturn
gst_av_sample_video_sink_prepare (GstBaseSink * bsink, GstBuffer * buf)
{
GstAVSampleVideoSink *av_sink;
av_sink = GST_AV_SAMPLE_VIDEO_SINK (bsink);
GST_LOG_OBJECT (bsink, "preparing buffer:%p", buf);
if (GST_VIDEO_SINK_WIDTH (av_sink) < 1 ||
GST_VIDEO_SINK_HEIGHT (av_sink) < 1) {
return GST_FLOW_NOT_NEGOTIATED;
}
return GST_FLOW_OK;
}
static GstFlowReturn
gst_av_sample_video_sink_show_frame (GstVideoSink * vsink, GstBuffer * buf)
{
GstAVSampleVideoSink *av_sink;
GstFlowReturn ret;
GST_TRACE_OBJECT (vsink, "rendering buffer:%p", buf);
av_sink = GST_AV_SAMPLE_VIDEO_SINK (vsink);
g_mutex_lock (&av_sink->render_lock);
if (av_sink->buffer)
gst_buffer_unref (av_sink->buffer);
av_sink->buffer = gst_buffer_ref (buf);
ret = av_sink->render_flow_return;
if (!av_sink->layer_requesting_data)
_request_data (av_sink);
g_mutex_unlock (&av_sink->render_lock);
if ([av_sink->layer status] == AVQueuedSampleBufferRenderingStatusFailed) {
GST_ERROR_OBJECT (av_sink, "failed to enqueue buffer on layer, %s",
[[[av_sink->layer error] description] UTF8String]);
return GST_FLOW_ERROR;
}
return GST_FLOW_OK;
return ret;
}
static gboolean