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4f04c9ac79
spice/server/gstreamer-encoder.c
Francois Gouget 4f04c9ac79 streaming: Shape the bit rate of the GStreamer codecs output 
The GStreamer codecs don't follow the specified bit rate very closely:
they can decide to exceed it for ten seconds or more if they consider
the scene deserves it. Such long bursts are enough to cause network
congestion, resulting in many lost frames which cause significant
display corruption.
So the GStreamer video encoder now uses a short 300ms virtual buffer
to shape the compressed video output and ensure we don't exceed the
target bit rate for any significant length of time.
It could instead rely on the network feedback (when available) to lower
the bit rate. However frequent GStreamer bit rate changes lower the
overall compression level and also result in a lower average bit rate,
both of which result in lower video quality.
The GStreamer video encoder also keeps track of the encoded frame size
so it can gather statistics and call update_client_playback_delay()
with accurate information and also annotate the client report debug
traces with the corresponding bit rate information.

Signed-off-by: Francois Gouget <fgouget@codeweavers.com>
2016-06-14 17:04:40 +02:00

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/* -*- Mode: C; c-basic-offset: 4; indent-tabs-mode: nil -*- */
/*
Copyright (C) 2015 Jeremy White
Copyright (C) 2015-2016 Francois Gouget
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, see <http://www.gnu.org/licenses/>.
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <gst/gst.h>
#include <gst/app/gstappsrc.h>
#include <gst/app/gstappsink.h>
#include "red-common.h"
#include "video-encoder.h"
#include "utils.h"
#define SPICE_GST_DEFAULT_FPS 30
#define DO_ZERO_COPY
typedef struct {
SpiceBitmapFmt spice_format;
const char *format;
uint32_t bpp;
} SpiceFormatForGStreamer;
typedef struct SpiceGstVideoBuffer {
VideoBuffer base;
GstBuffer *gst_buffer;
GstMapInfo map;
} SpiceGstVideoBuffer;
typedef struct {
uint32_t mm_time;
uint32_t size;
} SpiceGstFrameInformation;
typedef struct SpiceGstEncoder {
VideoEncoder base;
/* Callbacks to adjust the refcount of the bitmap being encoded. */
bitmap_ref_t bitmap_ref;
bitmap_unref_t bitmap_unref;
#ifdef DO_ZERO_COPY
GAsyncQueue *unused_bitmap_opaques;
#endif
/* Rate control callbacks */
VideoEncoderRateControlCbs cbs;
/* Spice's initial bit rate estimation in bits per second. */
uint64_t starting_bit_rate;
/* ---------- Video characteristics ---------- */
uint32_t width;
uint32_t height;
const SpiceFormatForGStreamer *format;
SpiceBitmapFmt spice_format;
/* ---------- GStreamer pipeline ---------- */
/* Pointers to the GStreamer pipeline elements. If pipeline is NULL the
* other pointers are invalid.
*/
GstElement *pipeline;
GstAppSink *appsink;
GstAppSrc *appsrc;
GstCaps *src_caps;
GstElement *gstenc;
/* Pipeline parameters to modify before the next frame. */
# define SPICE_GST_VIDEO_PIPELINE_STATE 0x1
# define SPICE_GST_VIDEO_PIPELINE_BITRATE 0x2
# define SPICE_GST_VIDEO_PIPELINE_CAPS 0x4
uint32_t set_pipeline;
/* Output buffer */
GMutex outbuf_mutex;
GCond outbuf_cond;
VideoBuffer *outbuf;
/* ---------- Encoded frame statistics ---------- */
/* Should be >= than FRAME_STATISTICS_COUNT. This is also used to
* annotate the client report debug traces with bit rate information.
*/
# define SPICE_GST_HISTORY_SIZE 60
/* A circular buffer containing the past encoded frames information. */
SpiceGstFrameInformation history[SPICE_GST_HISTORY_SIZE];
/* The indices of the oldest and newest frames in the history buffer. */
uint32_t history_first;
uint32_t history_last;
/* How many frames to take into account when computing the effective
* bit rate, average frame size, etc. This should be large enough so the
* I and P frames average out, and short enough for it to reflect the
* current situation.
*/
# define SPICE_GST_FRAME_STATISTICS_COUNT 21
/* The index of the oldest frame taken into account for the statistics. */
uint32_t stat_first;
/* Used to compute the average frame size. */
uint64_t stat_size_sum;
/* Tracks the maximum frame size. */
uint32_t stat_size_max;
/* ---------- Encoder bit rate control ----------
*
* GStreamer encoders don't follow the specified bit rate very
* closely. These fields are used to ensure we don't exceed the desired
* stream bit rate, regardless of the GStreamer encoder's output.
*/
/* The bit rate target for the outgoing network stream. (bits per second) */
uint64_t bit_rate;
/* The minimum bit rate. */
# define SPICE_GST_MIN_BITRATE (128 * 1024)
/* The default bit rate. */
# define SPICE_GST_DEFAULT_BITRATE (8 * 1024 * 1024)
/* The bit rate control is performed using a virtual buffer to allow
* short term variations: bursts are allowed until the virtual buffer is
* full. Then frames are dropped to limit the bit rate. VBUFFER_SIZE
* defines the size of the virtual buffer in milliseconds worth of data.
*/
# define SPICE_GST_VBUFFER_SIZE 300
int32_t vbuffer_size;
int32_t vbuffer_free;
/* When dropping frames, this is set to the minimum mm_time of the next
* frame to encode. Otherwise set to zero.
*/
uint32_t next_frame_mm_time;
/* Defines the minimum allowed fps. */
# define SPICE_GST_MAX_PERIOD (NSEC_PER_SEC / 3)
/* How big of a margin to take to cover for latency jitter. */
# define SPICE_GST_LATENCY_MARGIN 0.1
} SpiceGstEncoder;
/* ---------- The SpiceGstVideoBuffer implementation ---------- */
static void spice_gst_video_buffer_free(VideoBuffer *video_buffer)
{
SpiceGstVideoBuffer *buffer = (SpiceGstVideoBuffer*)video_buffer;
if (buffer->gst_buffer) {
gst_buffer_unmap(buffer->gst_buffer, &buffer->map);
gst_buffer_unref(buffer->gst_buffer);
}
free(buffer);
}
static SpiceGstVideoBuffer* create_gst_video_buffer(void)
{
SpiceGstVideoBuffer *buffer = spice_new0(SpiceGstVideoBuffer, 1);
buffer->base.free = spice_gst_video_buffer_free;
return buffer;
}
/* ---------- Miscellaneous SpiceGstEncoder helpers ---------- */
static inline double get_mbps(uint64_t bit_rate)
{
return (double)bit_rate / 1024 / 1024;
}
/* Returns the source frame rate which may change at any time so don't store
* the result.
*/
static uint32_t get_source_fps(SpiceGstEncoder *encoder)
{
return encoder->cbs.get_source_fps ?
encoder->cbs.get_source_fps(encoder->cbs.opaque) : SPICE_GST_DEFAULT_FPS;
}
static uint32_t get_network_latency(SpiceGstEncoder *encoder)
{
/* Assume that the network latency is symmetric */
return encoder->cbs.get_roundtrip_ms ?
encoder->cbs.get_roundtrip_ms(encoder->cbs.opaque) / 2 : 0;
}
static inline int rate_control_is_active(SpiceGstEncoder* encoder)
{
return encoder->cbs.get_roundtrip_ms != NULL;
}
static void set_pipeline_changes(SpiceGstEncoder *encoder, uint32_t flags)
{
encoder->set_pipeline |= flags;
}
static void free_pipeline(SpiceGstEncoder *encoder)
{
if (encoder->src_caps) {
gst_caps_unref(encoder->src_caps);
encoder->src_caps = NULL;
}
if (encoder->pipeline) {
gst_element_set_state(encoder->pipeline, GST_STATE_NULL);
gst_object_unref(encoder->appsrc);
gst_object_unref(encoder->gstenc);
gst_object_unref(encoder->appsink);
gst_object_unref(encoder->pipeline);
encoder->pipeline = NULL;
}
}
/* ---------- Encoded frame statistics ---------- */
static inline uint32_t get_last_frame_mm_time(SpiceGstEncoder *encoder)
{
return encoder->history[encoder->history_last].mm_time;
}
/* Returns the current bit rate based on the last
* SPICE_GST_FRAME_STATISTICS_COUNT frames.
*/
static uint64_t get_effective_bit_rate(SpiceGstEncoder *encoder)
{
uint32_t next_mm_time = encoder->next_frame_mm_time ?
encoder->next_frame_mm_time :
get_last_frame_mm_time(encoder) +
MSEC_PER_SEC / get_source_fps(encoder);
uint32_t elapsed = next_mm_time - encoder->history[encoder->stat_first].mm_time;
return elapsed ? encoder->stat_size_sum * 8 * MSEC_PER_SEC / elapsed : 0;
}
static uint64_t get_average_frame_size(SpiceGstEncoder *encoder)
{
uint32_t count = encoder->history_last +
(encoder->history_last < encoder->stat_first ? SPICE_GST_HISTORY_SIZE : 0) -
encoder->stat_first + 1;
return encoder->stat_size_sum / count;
}
static uint32_t get_maximum_frame_size(SpiceGstEncoder *encoder)
{
if (encoder->stat_size_max == 0) {
uint32_t index = encoder->history_last;
while (1) {
encoder->stat_size_max = MAX(encoder->stat_size_max,
encoder->history[index].size);
if (index == encoder->stat_first) {
break;
}
index = (index ? index : SPICE_GST_HISTORY_SIZE) - 1;
}
}
return encoder->stat_size_max;
}
/* Returns the bit rate of the specified period. from and to must be the
* mm time of the first and last frame to consider.
*/
static uint64_t get_period_bit_rate(SpiceGstEncoder *encoder, uint32_t from,
uint32_t to)
{
uint32_t sum = 0;
uint32_t last_mm_time = 0;
uint32_t index = encoder->history_last;
while (1) {
if (encoder->history[index].mm_time == to) {
if (last_mm_time == 0) {
/* We don't know how much time elapsed between the period's
* last frame and the next so we cannot include it.
*/
sum = 1;
last_mm_time = to;
} else {
sum = encoder->history[index].size + 1;
}
} else if (encoder->history[index].mm_time == from) {
sum += encoder->history[index].size;
return (sum - 1) * 8 * MSEC_PER_SEC / (last_mm_time - from);
} else if (index == encoder->history_first) {
/* This period is outside the recorded history */
spice_debug("period (%u-%u) outside known history (%u-%u)",
from, to,
encoder->history[encoder->history_first].mm_time,
encoder->history[encoder->history_last].mm_time);
return 0;
} else if (sum > 0) {
sum += encoder->history[index].size;
} else {
last_mm_time = encoder->history[index].mm_time;
}
index = (index ? index : SPICE_GST_HISTORY_SIZE) - 1;
}
}
static void add_frame(SpiceGstEncoder *encoder, uint32_t frame_mm_time,
uint32_t size)
{
/* Update the statistics */
uint32_t count = encoder->history_last +
(encoder->history_last < encoder->stat_first ? SPICE_GST_HISTORY_SIZE : 0) -
encoder->stat_first + 1;
if (count == SPICE_GST_FRAME_STATISTICS_COUNT) {
encoder->stat_size_sum -= encoder->history[encoder->stat_first].size;
if (encoder->stat_size_max == encoder->history[encoder->stat_first].size) {
encoder->stat_size_max = 0;
}
encoder->stat_first = (encoder->stat_first + 1) % SPICE_GST_HISTORY_SIZE;
}
encoder->stat_size_sum += size;
if (encoder->stat_size_max > 0 && size > encoder->stat_size_max) {
encoder->stat_size_max = size;
}
/* Update the frame history */
encoder->history_last = (encoder->history_last + 1) % SPICE_GST_HISTORY_SIZE;
if (encoder->history_last == encoder->history_first) {
encoder->history_first = (encoder->history_first + 1) % SPICE_GST_HISTORY_SIZE;
}
encoder->history[encoder->history_last].mm_time = frame_mm_time;
encoder->history[encoder->history_last].size = size;
}
/* ---------- Encoder bit rate control ---------- */
static uint32_t get_min_playback_delay(SpiceGstEncoder *encoder)
{
/* Make sure the delay is large enough to send a large frame (typically
* an I frame) and an average frame. This also takes into account the
* frames dropped by the encoder bit rate control.
*/
uint32_t size = get_maximum_frame_size(encoder) + get_average_frame_size(encoder);
uint32_t send_time = MSEC_PER_SEC * size * 8 / encoder->bit_rate;
/* Also factor in the network latency with a margin for jitter. */
uint32_t net_latency = get_network_latency(encoder) * (1.0 + SPICE_GST_LATENCY_MARGIN);
return send_time + net_latency;
}
static void update_client_playback_delay(SpiceGstEncoder *encoder)
{
if (encoder->cbs.update_client_playback_delay) {
uint32_t min_delay = get_min_playback_delay(encoder);
encoder->cbs.update_client_playback_delay(encoder->cbs.opaque, min_delay);
}
}
static void update_next_frame_mm_time(SpiceGstEncoder *encoder)
{
if (encoder->vbuffer_free >= 0) {
encoder->next_frame_mm_time = 0;
return;
}
/* Figure out how many frames to drop to not exceed the current bit rate.
* Use nanoseconds to avoid precision loss.
*/
uint64_t delay_ns = -encoder->vbuffer_free * 8 * NSEC_PER_SEC / encoder->bit_rate;
uint64_t period_ns = NSEC_PER_SEC / get_source_fps(encoder);
uint32_t drops = (delay_ns + period_ns - 1) / period_ns; /* round up */
spice_debug("drops=%u vbuffer %d/%d", drops, encoder->vbuffer_free,
encoder->vbuffer_size);
delay_ns = drops * period_ns + period_ns / 2;
if (delay_ns > SPICE_GST_MAX_PERIOD) {
delay_ns = SPICE_GST_MAX_PERIOD;
}
encoder->next_frame_mm_time = get_last_frame_mm_time(encoder) + delay_ns / NSEC_PER_MILLISEC;
/* Drops mean a higher delay between encoded frames so update the
* playback delay.
*/
update_client_playback_delay(encoder);
}
/* ---------- Network bit rate control ---------- */
/* The maximum bit rate we will use for the current video.
*
* This is based on a 10x compression ratio which should be more than enough
* for even MJPEG to provide good quality.
*/
static uint64_t get_bit_rate_cap(SpiceGstEncoder *encoder)
{
uint32_t raw_frame_bits = encoder->width * encoder->height * encoder->format->bpp;
return raw_frame_bits * get_source_fps(encoder) / 10;
}
static void adjust_bit_rate(SpiceGstEncoder *encoder)
{
if (encoder->bit_rate == 0) {
/* Use the default value, */
encoder->bit_rate = SPICE_GST_DEFAULT_BITRATE;
} else if (encoder->bit_rate < SPICE_GST_MIN_BITRATE) {
/* don't let the bit rate go too low */
encoder->bit_rate = SPICE_GST_MIN_BITRATE;
} else {
/* or too high */
encoder->bit_rate = MIN(encoder->bit_rate, get_bit_rate_cap(encoder));
}
spice_debug("adjust_bit_rate(%.3fMbps)", get_mbps(encoder->bit_rate));
}
/* ---------- GStreamer pipeline ---------- */
/* A helper for spice_gst_encoder_encode_frame() */
static const SpiceFormatForGStreamer *map_format(SpiceBitmapFmt format)
{
/* See GStreamer's part-mediatype-video-raw.txt and
* section-types-definitions.html documents.
*/
static const SpiceFormatForGStreamer format_map[] = {
{SPICE_BITMAP_FMT_RGBA, "BGRA", 32},
{SPICE_BITMAP_FMT_16BIT, "RGB15", 16},
/* TODO: Test the other formats */
{SPICE_BITMAP_FMT_32BIT, "BGRx", 32},
{SPICE_BITMAP_FMT_24BIT, "BGR", 24},
};
int i;
for (i = 0; i < G_N_ELEMENTS(format_map); i++) {
if (format_map[i].spice_format == format) {
if (i > 1) {
spice_warning("The %d format has not been tested yet", format);
}
return &format_map[i];
}
}
return NULL;
}
static void set_appsrc_caps(SpiceGstEncoder *encoder)
{
if (encoder->src_caps) {
gst_caps_unref(encoder->src_caps);
}
encoder->src_caps = gst_caps_new_simple(
"video/x-raw",
"format", G_TYPE_STRING, encoder->format->format,
"width", G_TYPE_INT, encoder->width,
"height", G_TYPE_INT, encoder->height,
"framerate", GST_TYPE_FRACTION, get_source_fps(encoder), 1,
NULL);
gst_app_src_set_caps(encoder->appsrc, encoder->src_caps);
}
static GstBusSyncReply handle_pipeline_message(GstBus *bus, GstMessage *msg, gpointer video_encoder)
{
SpiceGstEncoder *encoder = video_encoder;
if (GST_MESSAGE_TYPE(msg) == GST_MESSAGE_ERROR) {
GError *err = NULL;
gchar *debug_info = NULL;
gst_message_parse_error(msg, &err, &debug_info);
spice_warning("GStreamer error from element %s: %s",
GST_OBJECT_NAME(msg->src), err->message);
if (debug_info) {
spice_debug("debug details: %s", debug_info);
g_free(debug_info);
}
g_clear_error(&err);
/* Unblock the main thread */
g_mutex_lock(&encoder->outbuf_mutex);
encoder->outbuf = (VideoBuffer*)create_gst_video_buffer();
g_cond_signal(&encoder->outbuf_cond);
g_mutex_unlock(&encoder->outbuf_mutex);
}
return GST_BUS_PASS;
}
static GstFlowReturn new_sample(GstAppSink *gstappsink, gpointer video_encoder)
{
SpiceGstEncoder *encoder = (SpiceGstEncoder*)video_encoder;
SpiceGstVideoBuffer *outbuf = create_gst_video_buffer();
GstSample *sample = gst_app_sink_pull_sample(encoder->appsink);
if (sample) {
outbuf->gst_buffer = gst_sample_get_buffer(sample);
gst_buffer_ref(outbuf->gst_buffer);
gst_sample_unref(sample);
if (gst_buffer_map(outbuf->gst_buffer, &outbuf->map, GST_MAP_READ)) {
outbuf->base.data = outbuf->map.data;
outbuf->base.size = gst_buffer_get_size(outbuf->gst_buffer);
}
}
/* Notify the main thread that the output buffer is ready */
g_mutex_lock(&encoder->outbuf_mutex);
encoder->outbuf = (VideoBuffer*)outbuf;
g_cond_signal(&encoder->outbuf_cond);
g_mutex_unlock(&encoder->outbuf_mutex);
return GST_FLOW_OK;
}
static gboolean create_pipeline(SpiceGstEncoder *encoder)
{
gchar *gstenc;
switch (encoder->base.codec_type)
{
case SPICE_VIDEO_CODEC_TYPE_MJPEG:
/* Set max-threads to ensure zero-frame latency */
gstenc = g_strdup("avenc_mjpeg max-threads=1");
break;
case SPICE_VIDEO_CODEC_TYPE_VP8: {
/* See http://www.webmproject.org/docs/encoder-parameters/
* - Set end-usage to get a constant bitrate to help with streaming.
* - min-quantizer ensures the bitrate does not get needlessly high.
* - resize-allowed would be useful for low bitrate situations but
* the decoder does not return a frame of the expected size so
* avoid it.
* - error-resilient minimises artifacts in case the client drops a
* frame.
* - Set lag-in-frames, deadline and cpu-used to match
* "Profile Realtime". lag-in-frames ensures zero-frame latency,
* deadline turns on realtime behavior, and cpu-used targets a 75%
* CPU usage.
* - deadline is supposed to be set in microseconds but in practice
* it behaves like a boolean.
*/
gstenc = g_strdup_printf("vp8enc end-usage=cbr min-quantizer=10 error-resilient=default lag-in-frames=0 deadline=1 cpu-used=4");
break;
}
case SPICE_VIDEO_CODEC_TYPE_H264:
/* - Set tune and sliced-threads to ensure a zero-frame latency
* - qp-min ensures the bitrate does not get needlessly high.
* - Set speed-preset to get realtime speed.
* - Set intra-refresh to get more uniform compressed frame sizes,
* thus helping with streaming.
*/
gstenc = g_strdup("x264enc byte-stream=true aud=true qp-min=15 tune=4 sliced-threads=true speed-preset=ultrafast intra-refresh=true");
break;
default:
/* gstreamer_encoder_new() should have rejected this codec type */
spice_warning("unsupported codec type %d", encoder->base.codec_type);
return FALSE;
}
GError *err = NULL;
gchar *desc = g_strdup_printf("appsrc is-live=true format=time do-timestamp=true name=src ! videoconvert ! %s name=encoder ! appsink name=sink", gstenc);
spice_debug("GStreamer pipeline: %s", desc);
encoder->pipeline = gst_parse_launch_full(desc, NULL, GST_PARSE_FLAG_FATAL_ERRORS, &err);
g_free(gstenc);
g_free(desc);
if (!encoder->pipeline || err) {
spice_warning("GStreamer error: %s", err->message);
g_clear_error(&err);
if (encoder->pipeline) {
gst_object_unref(encoder->pipeline);
encoder->pipeline = NULL;
}
return FALSE;
}
encoder->appsrc = GST_APP_SRC(gst_bin_get_by_name(GST_BIN(encoder->pipeline), "src"));
encoder->gstenc = gst_bin_get_by_name(GST_BIN(encoder->pipeline), "encoder");
encoder->appsink = GST_APP_SINK(gst_bin_get_by_name(GST_BIN(encoder->pipeline), "sink"));
#ifdef HAVE_GSTREAMER_0_10
GstAppSinkCallbacks appsink_cbs = {NULL, NULL, &new_sample, NULL, {NULL}};
#else
GstAppSinkCallbacks appsink_cbs = {NULL, NULL, &new_sample, {NULL}};
#endif
gst_app_sink_set_callbacks(encoder->appsink, &appsink_cbs, encoder, NULL);
/* Hook into the bus so we can handle errors */
GstBus *bus = gst_element_get_bus(encoder->pipeline);
#ifdef HAVE_GSTREAMER_0_10
gst_bus_set_sync_handler(bus, handle_pipeline_message, encoder);
#else
gst_bus_set_sync_handler(bus, handle_pipeline_message, encoder, NULL);
#endif
gst_object_unref(bus);
if (encoder->base.codec_type == SPICE_VIDEO_CODEC_TYPE_MJPEG) {
/* See https://bugzilla.gnome.org/show_bug.cgi?id=753257 */
spice_debug("removing the pipeline clock");
gst_pipeline_use_clock(GST_PIPELINE(encoder->pipeline), NULL);
}
set_pipeline_changes(encoder, SPICE_GST_VIDEO_PIPELINE_STATE |
SPICE_GST_VIDEO_PIPELINE_BITRATE |
SPICE_GST_VIDEO_PIPELINE_CAPS);
return TRUE;
}
/* A helper for configure_pipeline() */
static void set_gstenc_bitrate(SpiceGstEncoder *encoder)
{
adjust_bit_rate(encoder);
switch (encoder->base.codec_type)
{
case SPICE_VIDEO_CODEC_TYPE_MJPEG:
g_object_set(G_OBJECT(encoder->gstenc),
"bitrate", (gint)encoder->bit_rate,
NULL);
break;
case SPICE_VIDEO_CODEC_TYPE_VP8:
g_object_set(G_OBJECT(encoder->gstenc),
"target-bitrate", (gint)encoder->bit_rate,
NULL);
break;
case SPICE_VIDEO_CODEC_TYPE_H264:
g_object_set(G_OBJECT(encoder->gstenc),
"bitrate", encoder->bit_rate / 1024,
NULL);
break;
default:
/* gstreamer_encoder_new() should have rejected this codec type */
spice_warning("unsupported codec type %d", encoder->base.codec_type);
free_pipeline(encoder);
}
}
/* A helper for spice_gst_encoder_encode_frame() */
static gboolean configure_pipeline(SpiceGstEncoder *encoder)
{
if (!encoder->pipeline && !create_pipeline(encoder)) {
return FALSE;
}
if (!encoder->set_pipeline) {
return TRUE;
}
/* If the pipeline state does not need to be changed it's because it is
* already in the PLAYING state. So first set it to the NULL state so it
* can be (re)configured.
*/
if (!(encoder->set_pipeline & SPICE_GST_VIDEO_PIPELINE_STATE) &&
gst_element_set_state(encoder->pipeline, GST_STATE_NULL) == GST_STATE_CHANGE_FAILURE) {
spice_debug("GStreamer error: could not stop the pipeline");
free_pipeline(encoder);
return FALSE;
}
/* Configure the encoder bitrate */
if (encoder->set_pipeline & SPICE_GST_VIDEO_PIPELINE_BITRATE) {
set_gstenc_bitrate(encoder);
}
/* Set the source caps */
if (encoder->set_pipeline & SPICE_GST_VIDEO_PIPELINE_CAPS) {
set_appsrc_caps(encoder);
}
/* Start playing */
if (gst_element_set_state(encoder->pipeline, GST_STATE_PLAYING) == GST_STATE_CHANGE_FAILURE) {
spice_warning("GStreamer error: unable to set the pipeline to the playing state");
free_pipeline(encoder);
return FALSE;
}
encoder->set_pipeline = 0;
return TRUE;
}
/* A helper for the *_copy() functions */
static int is_chunk_stride_aligned(const SpiceBitmap *bitmap, uint32_t index)
{
SpiceChunks *chunks = bitmap->data;
if (chunks->chunk[index].len % bitmap->stride != 0) {
/* A line straddles two chunks. This is not supported */
spice_warning("chunk %d/%d contains an incomplete line, cannot copy",
index, chunks->num_chunks);
return FALSE;
}
return TRUE;
}
/* A helper for push_raw_frame() */
static inline int line_copy(SpiceGstEncoder *encoder, const SpiceBitmap *bitmap,
uint32_t chunk_offset, uint32_t stream_stride,
uint32_t height, uint8_t *buffer)
{
uint8_t *dst = buffer;
SpiceChunks *chunks = bitmap->data;
uint32_t chunk_index = 0;
for (int l = 0; l < height; l++) {
/* We may have to move forward by more than one chunk the first
* time around. This also protects us against 0-byte chunks.
*/
while (chunk_offset >= chunks->chunk[chunk_index].len) {
if (!is_chunk_stride_aligned(bitmap, chunk_index)) {
return FALSE;
}
chunk_offset -= chunks->chunk[chunk_index].len;
chunk_index++;
}
/* Copy the line */
uint8_t *src = chunks->chunk[chunk_index].data + chunk_offset;
memcpy(dst, src, stream_stride);
dst += stream_stride;
chunk_offset += bitmap->stride;
}
spice_return_val_if_fail(dst - buffer == stream_stride * height, FALSE);
return TRUE;
}
#ifdef DO_ZERO_COPY
typedef struct {
gint refs;
SpiceGstEncoder *encoder;
gpointer opaque;
} BitmapWrapper;
static void clear_zero_copy_queue(SpiceGstEncoder *encoder, gboolean unref_queue)
{
gpointer bitmap_opaque;
while ((bitmap_opaque = g_async_queue_try_pop(encoder->unused_bitmap_opaques))) {
encoder->bitmap_unref(bitmap_opaque);
}
if (unref_queue) {
g_async_queue_unref(encoder->unused_bitmap_opaques);
}
}
static BitmapWrapper *bitmap_wrapper_new(SpiceGstEncoder *encoder, gpointer bitmap_opaque)
{
BitmapWrapper *wrapper = spice_new(BitmapWrapper, 1);
wrapper->refs = 1;
wrapper->encoder = encoder;
wrapper->opaque = bitmap_opaque;
encoder->bitmap_ref(bitmap_opaque);
return wrapper;
}
static void bitmap_wrapper_unref(gpointer data)
{
BitmapWrapper *wrapper = data;
if (g_atomic_int_dec_and_test(&wrapper->refs)) {
g_async_queue_push(wrapper->encoder->unused_bitmap_opaques, wrapper->opaque);
free(wrapper);
}
}
/* A helper for push_raw_frame() */
static inline int zero_copy(SpiceGstEncoder *encoder,
const SpiceBitmap *bitmap, gpointer bitmap_opaque,
GstBuffer *buffer, uint32_t *chunk_index,
uint32_t *chunk_offset, uint32_t *len)
{
const SpiceChunks *chunks = bitmap->data;
while (*chunk_index < chunks->num_chunks &&
*chunk_offset >= chunks->chunk[*chunk_index].len) {
if (!is_chunk_stride_aligned(bitmap, *chunk_index)) {
return FALSE;
}
*chunk_offset -= chunks->chunk[*chunk_index].len;
(*chunk_index)++;
}
int max_block_count = gst_buffer_get_max_memory();
if (chunks->num_chunks - *chunk_index > max_block_count) {
/* There are more chunks than we can fit memory objects in a
* buffer. This will cause the buffer to merge memory objects to
* fit the extra chunks, which means doing wasteful memory copies.
* So use the zero-copy approach for the first max_mem-1 chunks, and
* let push_raw_frame() deal with the rest.
*/
max_block_count = *chunk_index + max_block_count - 1;
} else {
max_block_count = chunks->num_chunks;
}
BitmapWrapper *wrapper = NULL;
while (*len && *chunk_index < max_block_count) {
if (!is_chunk_stride_aligned(bitmap, *chunk_index)) {
return FALSE;
}
if (wrapper) {
g_atomic_int_inc(&wrapper->refs);
} else {
wrapper = bitmap_wrapper_new(encoder, bitmap_opaque);
}
uint32_t thislen = MIN(chunks->chunk[*chunk_index].len - *chunk_offset, *len);
GstMemory *mem = gst_memory_new_wrapped(GST_MEMORY_FLAG_READONLY,
chunks->chunk[*chunk_index].data,
chunks->chunk[*chunk_index].len,
*chunk_offset, thislen,
wrapper, bitmap_wrapper_unref);
gst_buffer_append_memory(buffer, mem);
*len -= thislen;
*chunk_offset = 0;
(*chunk_index)++;
}
return TRUE;
}
#else
static void clear_zero_copy_queue(SpiceGstEncoder *encoder, gboolean unref_queue)
{
/* Nothing to do */
}
#endif
/* A helper for push_raw_frame() */
static inline int chunk_copy(SpiceGstEncoder *encoder, const SpiceBitmap *bitmap,
uint32_t chunk_index, uint32_t chunk_offset,
uint32_t len, uint8_t *dst)
{
SpiceChunks *chunks = bitmap->data;
/* Skip chunks until we find the start of the frame */
while (chunk_index < chunks->num_chunks &&
chunk_offset >= chunks->chunk[chunk_index].len) {
if (!is_chunk_stride_aligned(bitmap, chunk_index)) {
return FALSE;
}
chunk_offset -= chunks->chunk[chunk_index].len;
chunk_index++;
}
/* We can copy the frame chunk by chunk */
while (len && chunk_index < chunks->num_chunks) {
if (!is_chunk_stride_aligned(bitmap, chunk_index)) {
return FALSE;
}
uint8_t *src = chunks->chunk[chunk_index].data + chunk_offset;
uint32_t thislen = MIN(chunks->chunk[chunk_index].len - chunk_offset, len);
memcpy(dst, src, thislen);
dst += thislen;
len -= thislen;
chunk_offset = 0;
chunk_index++;
}
spice_return_val_if_fail(len == 0, FALSE);
return TRUE;
}
/* A helper for push_raw_frame() */
static uint8_t *allocate_and_map_memory(gsize size, GstMapInfo *map, GstBuffer *buffer)
{
GstMemory *mem = gst_allocator_alloc(NULL, size, NULL);
if (!mem) {
gst_buffer_unref(buffer);
return NULL;
}
if (!gst_memory_map(mem, map, GST_MAP_WRITE)) {
gst_memory_unref(mem);
gst_buffer_unref(buffer);
return NULL;
}
return map->data;
}
/* A helper for spice_gst_encoder_encode_frame() */
static int push_raw_frame(SpiceGstEncoder *encoder,
const SpiceBitmap *bitmap,
const SpiceRect *src, int top_down,
gpointer bitmap_opaque)
{
uint32_t height = src->bottom - src->top;
uint32_t stream_stride = (src->right - src->left) * encoder->format->bpp / 8;
uint32_t len = stream_stride * height;
GstBuffer *buffer = gst_buffer_new();
/* TODO Use GST_MAP_INFO_INIT once GStreamer 1.4.5 is no longer relevant */
GstMapInfo map = { .memory = NULL };
/* Note that we should not reorder the lines, even if top_down is false.
* It just changes the number of lines to skip at the start of the bitmap.
*/
uint32_t skip_lines = top_down ? src->top : bitmap->y - (src->bottom - 0);
uint32_t chunk_offset = bitmap->stride * skip_lines;
if (stream_stride != bitmap->stride) {
/* We have to do a line-by-line copy because for each we have to
* leave out pixels on the left or right.
*/
uint8_t *dst = allocate_and_map_memory(len, &map, buffer);
if (!dst) {
return VIDEO_ENCODER_FRAME_UNSUPPORTED;
}
chunk_offset += src->left * encoder->format->bpp / 8;
if (!line_copy(encoder, bitmap, chunk_offset, stream_stride, height, dst)) {
gst_memory_unmap(map.memory, &map);
gst_memory_unref(map.memory);
gst_buffer_unref(buffer);
return VIDEO_ENCODER_FRAME_UNSUPPORTED;
}
} else {
/* We can copy the bitmap chunk by chunk */
uint32_t chunk_index = 0;
#ifdef DO_ZERO_COPY
if (!zero_copy(encoder, bitmap, bitmap_opaque, buffer, &chunk_index,
&chunk_offset, &len)) {
gst_buffer_unref(buffer);
return VIDEO_ENCODER_FRAME_UNSUPPORTED;
}
/* len now contains the remaining number of bytes to copy.
* However we must avoid any write to the GstBuffer object as it
* would cause a copy of the read-only memory objects we just added.
* Fortunately we can append extra writable memory objects instead.
*/
#endif
if (len) {
uint8_t *dst = allocate_and_map_memory(len, &map, buffer);
if (!dst) {
return VIDEO_ENCODER_FRAME_UNSUPPORTED;
}
if (!chunk_copy(encoder, bitmap, chunk_index, chunk_offset, len, dst)) {
gst_memory_unmap(map.memory, &map);
gst_memory_unref(map.memory);
gst_buffer_unref(buffer);
return VIDEO_ENCODER_FRAME_UNSUPPORTED;
}
}
}
if (map.memory) {
gst_memory_unmap(map.memory, &map);
gst_buffer_append_memory(buffer, map.memory);
}
GstFlowReturn ret = gst_app_src_push_buffer(encoder->appsrc, buffer);
if (ret != GST_FLOW_OK) {
spice_warning("GStreamer error: unable to push source buffer (%d)", ret);
return VIDEO_ENCODER_FRAME_UNSUPPORTED;
}
return VIDEO_ENCODER_FRAME_ENCODE_DONE;
}
/* A helper for spice_gst_encoder_encode_frame() */
static int pull_compressed_buffer(SpiceGstEncoder *encoder,
VideoBuffer **outbuf)
{
g_mutex_lock(&encoder->outbuf_mutex);
while (!encoder->outbuf) {
g_cond_wait(&encoder->outbuf_cond, &encoder->outbuf_mutex);
}
*outbuf = encoder->outbuf;
encoder->outbuf = NULL;
g_mutex_unlock(&encoder->outbuf_mutex);
if ((*outbuf)->data) {
return VIDEO_ENCODER_FRAME_ENCODE_DONE;
}
spice_debug("failed to pull the compressed buffer");
(*outbuf)->free(*outbuf);
*outbuf = NULL;
return VIDEO_ENCODER_FRAME_UNSUPPORTED;
}
/* ---------- VideoEncoder's public API ---------- */
static void spice_gst_encoder_destroy(VideoEncoder *video_encoder)
{
SpiceGstEncoder *encoder = (SpiceGstEncoder*)video_encoder;
free_pipeline(encoder);
g_mutex_clear(&encoder->outbuf_mutex);
g_cond_clear(&encoder->outbuf_cond);
/* Unref any lingering bitmap opaque structures from past frames */
clear_zero_copy_queue(encoder, TRUE);
free(encoder);
}
static int spice_gst_encoder_encode_frame(VideoEncoder *video_encoder,
uint32_t frame_mm_time,
const SpiceBitmap *bitmap,
const SpiceRect *src, int top_down,
gpointer bitmap_opaque,
VideoBuffer **outbuf)
{
SpiceGstEncoder *encoder = (SpiceGstEncoder*)video_encoder;
g_return_val_if_fail(outbuf != NULL, VIDEO_ENCODER_FRAME_UNSUPPORTED);
*outbuf = NULL;
/* Unref the last frame's bitmap_opaque structures if any */
clear_zero_copy_queue(encoder, FALSE);
uint32_t width = src->right - src->left;
uint32_t height = src->bottom - src->top;
if (width != encoder->width || height != encoder->height ||
encoder->spice_format != bitmap->format) {
spice_debug("video format change: width %d -> %d, height %d -> %d, format %d -> %d",
encoder->width, width, encoder->height, height,
encoder->spice_format, bitmap->format);
encoder->format = map_format(bitmap->format);
if (!encoder->format) {
spice_warning("unable to map format type %d", bitmap->format);
return VIDEO_ENCODER_FRAME_UNSUPPORTED;
}
encoder->spice_format = bitmap->format;
encoder->width = width;
encoder->height = height;
if (encoder->bit_rate == 0) {
encoder->history[0].mm_time = frame_mm_time;
encoder->bit_rate = encoder->starting_bit_rate;
adjust_bit_rate(encoder);
encoder->vbuffer_free = 0; /* Slow start */
} else if (encoder->pipeline) {
set_pipeline_changes(encoder, SPICE_GST_VIDEO_PIPELINE_CAPS);
}
}
if (rate_control_is_active(encoder) &&
frame_mm_time < encoder->next_frame_mm_time) {
/* Drop the frame to limit the outgoing bit rate. */
return VIDEO_ENCODER_FRAME_DROP;
}
if (!configure_pipeline(encoder)) {
return VIDEO_ENCODER_FRAME_UNSUPPORTED;
}
int rc = push_raw_frame(encoder, bitmap, src, top_down, bitmap_opaque);
if (rc == VIDEO_ENCODER_FRAME_ENCODE_DONE) {
rc = pull_compressed_buffer(encoder, outbuf);
if (rc != VIDEO_ENCODER_FRAME_ENCODE_DONE) {
/* The input buffer will be stuck in the pipeline, preventing
* later ones from being processed. Furthermore something went
* wrong with this pipeline, so it may be safer to rebuild it
* from scratch.
*/
free_pipeline(encoder);
}
}
/* Unref the last frame's bitmap_opaque structures if any */
clear_zero_copy_queue(encoder, FALSE);
if (rc != VIDEO_ENCODER_FRAME_ENCODE_DONE) {
return rc;
}
add_frame(encoder, frame_mm_time, (*outbuf)->size);
update_next_frame_mm_time(encoder);
return rc;
}
static void spice_gst_encoder_client_stream_report(VideoEncoder *video_encoder,
uint32_t num_frames,
uint32_t num_drops,
uint32_t start_frame_mm_time,
uint32_t end_frame_mm_time,
int32_t end_frame_delay,
uint32_t audio_delay)
{
SpiceGstEncoder *encoder = (SpiceGstEncoder*)video_encoder;
uint64_t period_bit_rate = get_period_bit_rate(encoder, start_frame_mm_time, end_frame_mm_time);
spice_debug("client report: %u/%u drops in %ums margins video %3d audio %3u bw %.3f/%.3fMbps",
num_drops, num_frames, end_frame_mm_time - start_frame_mm_time,
end_frame_delay, audio_delay,
get_mbps(period_bit_rate),
get_mbps(get_effective_bit_rate(encoder)));
}
static void spice_gst_encoder_notify_server_frame_drop(VideoEncoder *video_encoder)
{
spice_debug("server report: getting frame drops...");
}
static uint64_t spice_gst_encoder_get_bit_rate(VideoEncoder *video_encoder)
{
SpiceGstEncoder *encoder = (SpiceGstEncoder*)video_encoder;
return get_effective_bit_rate(encoder);
}
static void spice_gst_encoder_get_stats(VideoEncoder *video_encoder,
VideoEncoderStats *stats)
{
SpiceGstEncoder *encoder = (SpiceGstEncoder*)video_encoder;
uint64_t raw_bit_rate = encoder->width * encoder->height * (encoder->format ? encoder->format->bpp : 0) * get_source_fps(encoder);
spice_return_if_fail(stats != NULL);
stats->starting_bit_rate = encoder->starting_bit_rate;
stats->cur_bit_rate = get_effective_bit_rate(encoder);
/* Use the compression level as a proxy for the quality */
stats->avg_quality = stats->cur_bit_rate ? 100.0 - raw_bit_rate / stats->cur_bit_rate : 0;
if (stats->avg_quality < 0) {
stats->avg_quality = 0;
}
}
VideoEncoder *gstreamer_encoder_new(SpiceVideoCodecType codec_type,
uint64_t starting_bit_rate,
VideoEncoderRateControlCbs *cbs,
bitmap_ref_t bitmap_ref,
bitmap_unref_t bitmap_unref)
{
spice_return_val_if_fail(SPICE_GST_FRAME_STATISTICS_COUNT <= SPICE_GST_HISTORY_SIZE, NULL);
spice_return_val_if_fail(codec_type == SPICE_VIDEO_CODEC_TYPE_MJPEG ||
codec_type == SPICE_VIDEO_CODEC_TYPE_VP8 ||
codec_type == SPICE_VIDEO_CODEC_TYPE_H264, NULL);
GError *err = NULL;
if (!gst_init_check(NULL, NULL, &err)) {
spice_warning("GStreamer error: %s", err->message);
g_clear_error(&err);
return NULL;
}
SpiceGstEncoder *encoder = spice_new0(SpiceGstEncoder, 1);
encoder->base.destroy = spice_gst_encoder_destroy;
encoder->base.encode_frame = spice_gst_encoder_encode_frame;
encoder->base.client_stream_report = spice_gst_encoder_client_stream_report;
encoder->base.notify_server_frame_drop = spice_gst_encoder_notify_server_frame_drop;
encoder->base.get_bit_rate = spice_gst_encoder_get_bit_rate;
encoder->base.get_stats = spice_gst_encoder_get_stats;
encoder->base.codec_type = codec_type;
#ifdef DO_ZERO_COPY
encoder->unused_bitmap_opaques = g_async_queue_new();
#endif
if (cbs) {
encoder->cbs = *cbs;
}
encoder->starting_bit_rate = starting_bit_rate;
encoder->bitmap_ref = bitmap_ref;
encoder->bitmap_unref = bitmap_unref;
g_mutex_init(&encoder->outbuf_mutex);
g_cond_init(&encoder->outbuf_cond);
/* All the other fields are initialized to zero by spice_new0(). */
if (!create_pipeline(encoder)) {
/* Some GStreamer dependency is probably missing */
free(encoder);
encoder = NULL;
}
return (VideoEncoder*)encoder;
}
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