1 // Copyright 2013 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
5 // TODO (pwestin): add a link to the design document describing the generic
6 // protocol and the VP8 specific details.
7 #include "media/cast/video_sender/codecs/vp8/vp8_encoder.h"
11 #include "base/logging.h"
12 #include "media/base/video_frame.h"
13 #include "media/cast/cast_defines.h"
14 #include "media/cast/transport/cast_transport_config.h"
15 #include "third_party/libvpx/source/libvpx/vpx/vp8cx.h"
20 static const uint32 kMinIntra = 300;
22 static int ComputeMaxNumOfRepeatedBuffes(uint8 max_unacked_frames) {
23 if (max_unacked_frames > kNumberOfVp8VideoBuffers)
24 return (max_unacked_frames - 1) / kNumberOfVp8VideoBuffers;
29 Vp8Encoder::Vp8Encoder(const VideoSenderConfig& video_config,
30 uint8 max_unacked_frames)
31 : cast_config_(video_config),
32 use_multiple_video_buffers_(
33 cast_config_.max_number_of_video_buffers_used ==
34 kNumberOfVp8VideoBuffers),
35 max_number_of_repeated_buffers_in_a_row_(
36 ComputeMaxNumOfRepeatedBuffes(max_unacked_frames)),
37 key_frame_requested_(true),
39 last_encoded_frame_id_(kStartFrameId),
40 number_of_repeated_buffers_(0) {
41 // TODO(pwestin): we need to figure out how to synchronize the acking with the
42 // internal state of the encoder, ideally the encoder will tell if we can
43 // send another frame.
44 DCHECK(!use_multiple_video_buffers_ ||
45 max_number_of_repeated_buffers_in_a_row_ == 0)
48 // VP8 have 3 buffers available for prediction, with
49 // max_number_of_video_buffers_used set to 1 we maximize the coding efficiency
50 // however in this mode we can not skip frames in the receiver to catch up
51 // after a temporary network outage; with max_number_of_video_buffers_used
52 // set to 3 we allow 2 frames to be skipped by the receiver without error
54 DCHECK(cast_config_.max_number_of_video_buffers_used == 1 ||
55 cast_config_.max_number_of_video_buffers_used ==
56 kNumberOfVp8VideoBuffers)
57 << "Invalid argument";
59 thread_checker_.DetachFromThread();
62 Vp8Encoder::~Vp8Encoder() {
63 vpx_codec_destroy(encoder_.get());
64 vpx_img_free(raw_image_);
67 void Vp8Encoder::Initialize() {
68 DCHECK(thread_checker_.CalledOnValidThread());
69 config_.reset(new vpx_codec_enc_cfg_t());
70 encoder_.reset(new vpx_codec_ctx_t());
72 // Creating a wrapper to the image - setting image data to NULL. Actual
73 // pointer will be set during encode. Setting align to 1, as it is
74 // meaningless (actual memory is not allocated).
75 raw_image_ = vpx_img_wrap(
76 NULL, IMG_FMT_I420, cast_config_.width, cast_config_.height, 1, NULL);
78 for (int i = 0; i < kNumberOfVp8VideoBuffers; ++i) {
79 acked_frame_buffers_[i] = true;
80 used_buffers_frame_id_[i] = kStartFrameId;
82 InitEncode(cast_config_.number_of_cores);
85 void Vp8Encoder::InitEncode(int number_of_cores) {
86 DCHECK(thread_checker_.CalledOnValidThread());
87 // Populate encoder configuration with default values.
88 if (vpx_codec_enc_config_default(vpx_codec_vp8_cx(), config_.get(), 0)) {
89 DCHECK(false) << "Invalid return value";
91 config_->g_w = cast_config_.width;
92 config_->g_h = cast_config_.height;
93 config_->rc_target_bitrate = cast_config_.start_bitrate / 1000; // In kbit/s.
95 // Setting the codec time base.
96 config_->g_timebase.num = 1;
97 config_->g_timebase.den = kVideoFrequency;
98 config_->g_lag_in_frames = 0;
99 config_->kf_mode = VPX_KF_DISABLED;
100 if (use_multiple_video_buffers_) {
101 // We must enable error resilience when we use multiple buffers, due to
102 // codec requirements.
103 config_->g_error_resilient = 1;
106 if (cast_config_.width * cast_config_.height > 640 * 480 &&
107 number_of_cores >= 2) {
108 config_->g_threads = 2; // 2 threads for qHD/HD.
110 config_->g_threads = 1; // 1 thread for VGA or less.
113 // Rate control settings.
114 // TODO(pwestin): revisit these constants. Currently identical to webrtc.
115 config_->rc_dropframe_thresh = 30;
116 config_->rc_end_usage = VPX_CBR;
117 config_->g_pass = VPX_RC_ONE_PASS;
118 config_->rc_resize_allowed = 0;
119 config_->rc_min_quantizer = cast_config_.min_qp;
120 config_->rc_max_quantizer = cast_config_.max_qp;
121 config_->rc_undershoot_pct = 100;
122 config_->rc_overshoot_pct = 15;
123 config_->rc_buf_initial_sz = 500;
124 config_->rc_buf_optimal_sz = 600;
125 config_->rc_buf_sz = 1000;
127 // set the maximum target size of any key-frame.
128 uint32 rc_max_intra_target = MaxIntraTarget(config_->rc_buf_optimal_sz);
129 vpx_codec_flags_t flags = 0;
130 // TODO(mikhal): Tune settings.
131 if (vpx_codec_enc_init(
132 encoder_.get(), vpx_codec_vp8_cx(), config_.get(), flags)) {
133 DCHECK(false) << "vpx_codec_enc_init() failed.";
137 vpx_codec_control(encoder_.get(), VP8E_SET_STATIC_THRESHOLD, 1);
138 vpx_codec_control(encoder_.get(), VP8E_SET_NOISE_SENSITIVITY, 0);
139 vpx_codec_control(encoder_.get(), VP8E_SET_CPUUSED, -6);
141 encoder_.get(), VP8E_SET_MAX_INTRA_BITRATE_PCT, rc_max_intra_target);
144 bool Vp8Encoder::Encode(const scoped_refptr<media::VideoFrame>& video_frame,
145 transport::EncodedVideoFrame* encoded_image) {
146 DCHECK(thread_checker_.CalledOnValidThread());
147 // Image in vpx_image_t format.
148 // Input image is const. VP8's raw image is not defined as const.
149 raw_image_->planes[PLANE_Y] =
150 const_cast<uint8*>(video_frame->data(VideoFrame::kYPlane));
151 raw_image_->planes[PLANE_U] =
152 const_cast<uint8*>(video_frame->data(VideoFrame::kUPlane));
153 raw_image_->planes[PLANE_V] =
154 const_cast<uint8*>(video_frame->data(VideoFrame::kVPlane));
156 raw_image_->stride[VPX_PLANE_Y] = video_frame->stride(VideoFrame::kYPlane);
157 raw_image_->stride[VPX_PLANE_U] = video_frame->stride(VideoFrame::kUPlane);
158 raw_image_->stride[VPX_PLANE_V] = video_frame->stride(VideoFrame::kVPlane);
160 uint8 latest_frame_id_to_reference;
161 Vp8Buffers buffer_to_update;
162 vpx_codec_flags_t flags = 0;
163 if (key_frame_requested_) {
164 flags = VPX_EFLAG_FORCE_KF;
166 latest_frame_id_to_reference = last_encoded_frame_id_ + 1;
167 // We can pick any buffer as buffer_to_update since we update
169 buffer_to_update = kLastBuffer;
171 // Reference all acked frames (buffers).
172 latest_frame_id_to_reference = GetLatestFrameIdToReference();
173 GetCodecReferenceFlags(&flags);
174 buffer_to_update = GetNextBufferToUpdate();
175 GetCodecUpdateFlags(buffer_to_update, &flags);
178 // Note: The duration does not reflect the real time between frames. This is
179 // done to keep the encoder happy.
180 uint32 duration = kVideoFrequency / cast_config_.max_frame_rate;
181 if (vpx_codec_encode(encoder_.get(),
189 timestamp_ += duration;
191 // Get encoded frame.
192 const vpx_codec_cx_pkt_t* pkt = NULL;
193 vpx_codec_iter_t iter = NULL;
194 size_t total_size = 0;
195 while ((pkt = vpx_codec_get_cx_data(encoder_.get(), &iter)) != NULL) {
196 if (pkt->kind == VPX_CODEC_CX_FRAME_PKT) {
197 total_size += pkt->data.frame.sz;
198 encoded_image->data.reserve(total_size);
199 encoded_image->data.insert(
200 encoded_image->data.end(),
201 static_cast<const uint8*>(pkt->data.frame.buf),
202 static_cast<const uint8*>(pkt->data.frame.buf) + pkt->data.frame.sz);
203 if (pkt->data.frame.flags & VPX_FRAME_IS_KEY) {
204 encoded_image->key_frame = true;
206 encoded_image->key_frame = false;
210 // Don't update frame_id for zero size frames.
214 // Populate the encoded frame.
215 encoded_image->codec = transport::kVp8;
216 encoded_image->last_referenced_frame_id = latest_frame_id_to_reference;
217 encoded_image->frame_id = ++last_encoded_frame_id_;
219 VLOG(1) << "VP8 encoded frame:" << static_cast<int>(encoded_image->frame_id)
220 << " sized:" << total_size;
222 if (encoded_image->key_frame) {
223 key_frame_requested_ = false;
225 for (int i = 0; i < kNumberOfVp8VideoBuffers; ++i) {
226 used_buffers_frame_id_[i] = encoded_image->frame_id;
228 // We can pick any buffer as last_used_vp8_buffer_ since we update
230 last_used_vp8_buffer_ = buffer_to_update;
232 if (buffer_to_update != kNoBuffer) {
233 acked_frame_buffers_[buffer_to_update] = false;
234 used_buffers_frame_id_[buffer_to_update] = encoded_image->frame_id;
235 last_used_vp8_buffer_ = buffer_to_update;
241 void Vp8Encoder::GetCodecReferenceFlags(vpx_codec_flags_t* flags) {
242 if (!use_multiple_video_buffers_)
245 // We need to reference something.
246 DCHECK(acked_frame_buffers_[kAltRefBuffer] ||
247 acked_frame_buffers_[kGoldenBuffer] ||
248 acked_frame_buffers_[kLastBuffer])
251 if (!acked_frame_buffers_[kAltRefBuffer]) {
252 *flags |= VP8_EFLAG_NO_REF_ARF;
254 if (!acked_frame_buffers_[kGoldenBuffer]) {
255 *flags |= VP8_EFLAG_NO_REF_GF;
257 if (!acked_frame_buffers_[kLastBuffer]) {
258 *flags |= VP8_EFLAG_NO_REF_LAST;
262 uint32 Vp8Encoder::GetLatestFrameIdToReference() {
263 if (!use_multiple_video_buffers_)
264 return last_encoded_frame_id_;
266 int latest_frame_id_to_reference = -1;
267 if (acked_frame_buffers_[kAltRefBuffer]) {
268 latest_frame_id_to_reference = used_buffers_frame_id_[kAltRefBuffer];
270 if (acked_frame_buffers_[kGoldenBuffer]) {
271 if (latest_frame_id_to_reference == -1) {
272 latest_frame_id_to_reference = used_buffers_frame_id_[kGoldenBuffer];
274 if (IsNewerFrameId(used_buffers_frame_id_[kGoldenBuffer],
275 latest_frame_id_to_reference)) {
276 latest_frame_id_to_reference = used_buffers_frame_id_[kGoldenBuffer];
280 if (acked_frame_buffers_[kLastBuffer]) {
281 if (latest_frame_id_to_reference == -1) {
282 latest_frame_id_to_reference = used_buffers_frame_id_[kLastBuffer];
284 if (IsNewerFrameId(used_buffers_frame_id_[kLastBuffer],
285 latest_frame_id_to_reference)) {
286 latest_frame_id_to_reference = used_buffers_frame_id_[kLastBuffer];
290 DCHECK(latest_frame_id_to_reference != -1) << "Invalid state";
291 return static_cast<uint32>(latest_frame_id_to_reference);
294 Vp8Encoder::Vp8Buffers Vp8Encoder::GetNextBufferToUpdate() {
295 // Update at most one buffer, except for key-frames.
297 Vp8Buffers buffer_to_update;
298 if (number_of_repeated_buffers_ < max_number_of_repeated_buffers_in_a_row_) {
299 // TODO(pwestin): experiment with this. The issue with only this change is
300 // that we can end up with only 4 frames in flight when we expect 6.
301 // buffer_to_update = last_used_vp8_buffer_;
302 buffer_to_update = kNoBuffer;
303 ++number_of_repeated_buffers_;
305 number_of_repeated_buffers_ = 0;
306 switch (last_used_vp8_buffer_) {
308 buffer_to_update = kLastBuffer;
309 VLOG(1) << "VP8 update last buffer";
312 buffer_to_update = kGoldenBuffer;
313 VLOG(1) << "VP8 update golden buffer";
316 buffer_to_update = kAltRefBuffer;
317 VLOG(1) << "VP8 update alt-ref buffer";
320 DCHECK(false) << "Invalid state";
324 return buffer_to_update;
327 void Vp8Encoder::GetCodecUpdateFlags(Vp8Buffers buffer_to_update,
328 vpx_codec_flags_t* flags) {
329 if (!use_multiple_video_buffers_)
332 // Update at most one buffer, except for key-frames.
333 switch (buffer_to_update) {
335 *flags |= VP8_EFLAG_NO_UPD_GF;
336 *flags |= VP8_EFLAG_NO_UPD_LAST;
339 *flags |= VP8_EFLAG_NO_UPD_GF;
340 *flags |= VP8_EFLAG_NO_UPD_ARF;
343 *flags |= VP8_EFLAG_NO_UPD_ARF;
344 *flags |= VP8_EFLAG_NO_UPD_LAST;
347 *flags |= VP8_EFLAG_NO_UPD_ARF;
348 *flags |= VP8_EFLAG_NO_UPD_GF;
349 *flags |= VP8_EFLAG_NO_UPD_LAST;
350 *flags |= VP8_EFLAG_NO_UPD_ENTROPY;
355 void Vp8Encoder::UpdateRates(uint32 new_bitrate) {
356 DCHECK(thread_checker_.CalledOnValidThread());
357 uint32 new_bitrate_kbit = new_bitrate / 1000;
358 if (config_->rc_target_bitrate == new_bitrate_kbit)
361 config_->rc_target_bitrate = new_bitrate_kbit;
363 // Update encoder context.
364 if (vpx_codec_enc_config_set(encoder_.get(), config_.get())) {
365 DCHECK(false) << "Invalid return value";
369 void Vp8Encoder::LatestFrameIdToReference(uint32 frame_id) {
370 DCHECK(thread_checker_.CalledOnValidThread());
371 if (!use_multiple_video_buffers_)
374 VLOG(1) << "VP8 ok to reference frame:" << static_cast<int>(frame_id);
375 for (int i = 0; i < kNumberOfVp8VideoBuffers; ++i) {
376 if (frame_id == used_buffers_frame_id_[i]) {
377 acked_frame_buffers_[i] = true;
382 void Vp8Encoder::GenerateKeyFrame() {
383 DCHECK(thread_checker_.CalledOnValidThread());
384 key_frame_requested_ = true;
387 // Calculate the max size of the key frame relative to a normal delta frame.
388 uint32 Vp8Encoder::MaxIntraTarget(uint32 optimal_buffer_size_ms) const {
389 // Set max to the optimal buffer level (normalized by target BR),
390 // and scaled by a scale_parameter.
391 // Max target size = scalePar * optimalBufferSize * targetBR[Kbps].
392 // This values is presented in percentage of perFrameBw:
393 // perFrameBw = targetBR[Kbps] * 1000 / frameRate.
394 // The target in % is as follows:
396 float scale_parameter = 0.5;
397 uint32 target_pct = optimal_buffer_size_ms * scale_parameter *
398 cast_config_.max_frame_rate / 10;
400 // Don't go below 3 times the per frame bandwidth.
401 return std::max(target_pct, kMinIntra);