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// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "media/formats/mp2t/es_adapter_video.h"
#include "media/base/buffers.h"
#include "media/base/stream_parser_buffer.h"
#include "media/base/video_decoder_config.h"
#include "media/formats/mp2t/mp2t_common.h"
namespace media {
namespace mp2t {
// Arbitrary decision about the frame duration when there is no previous
// hint about what could be the frame duration.
static const int kDefaultFrameDurationMs = 40;
// To calculate the frame duration, we make an assumption
// that the timestamp of the next frame in presentation order
// is no further than 5 frames away in decode order.
// TODO(damienv): the previous assumption should cover most of the practical
// cases. However, the right way to calculate the frame duration would be
// to emulate the H264 dpb bumping process.
static const size_t kHistorySize = 5;
EsAdapterVideo::EsAdapterVideo(
const NewVideoConfigCB& new_video_config_cb,
const EmitBufferCB& emit_buffer_cb)
: new_video_config_cb_(new_video_config_cb),
emit_buffer_cb_(emit_buffer_cb),
has_valid_config_(false),
has_valid_frame_(false),
last_frame_duration_(
base::TimeDelta::FromMilliseconds(kDefaultFrameDurationMs)),
buffer_index_(0) {
}
EsAdapterVideo::~EsAdapterVideo() {
}
void EsAdapterVideo::Flush() {
ProcessPendingBuffers(true);
}
void EsAdapterVideo::Reset() {
has_valid_config_ = false;
has_valid_frame_ = false;
last_frame_duration_ =
base::TimeDelta::FromMilliseconds(kDefaultFrameDurationMs);
config_list_.clear();
buffer_index_ = 0;
buffer_list_.clear();
emitted_pts_.clear();
discarded_frames_min_pts_ = base::TimeDelta();
discarded_frames_dts_.clear();
}
void EsAdapterVideo::OnConfigChanged(
const VideoDecoderConfig& video_decoder_config) {
config_list_.push_back(
ConfigEntry(buffer_index_ + buffer_list_.size(), video_decoder_config));
has_valid_config_ = true;
ProcessPendingBuffers(false);
}
void EsAdapterVideo::OnNewBuffer(
const scoped_refptr<StreamParserBuffer>& stream_parser_buffer) {
// Discard the incoming frame:
// - if it is not associated with any config,
// - or if only non-key frames have been added to a new segment.
if (!has_valid_config_ ||
(!has_valid_frame_ && !stream_parser_buffer->IsKeyframe())) {
if (discarded_frames_dts_.empty() ||
discarded_frames_min_pts_ > stream_parser_buffer->timestamp()) {
discarded_frames_min_pts_ = stream_parser_buffer->timestamp();
}
discarded_frames_dts_.push_back(
stream_parser_buffer->GetDecodeTimestamp());
return;
}
has_valid_frame_ = true;
if (!discarded_frames_dts_.empty())
ReplaceDiscardedFrames(stream_parser_buffer);
buffer_list_.push_back(stream_parser_buffer);
ProcessPendingBuffers(false);
}
void EsAdapterVideo::ProcessPendingBuffers(bool flush) {
DCHECK(has_valid_config_);
while (!buffer_list_.empty() &&
(flush || buffer_list_.size() > kHistorySize)) {
// Signal a config change, just before emitting the corresponding frame.
if (!config_list_.empty() && config_list_.front().first == buffer_index_) {
new_video_config_cb_.Run(config_list_.front().second);
config_list_.pop_front();
}
scoped_refptr<StreamParserBuffer> buffer = buffer_list_.front();
buffer_list_.pop_front();
buffer_index_++;
if (buffer->duration() == kNoTimestamp()) {
base::TimeDelta next_frame_pts = GetNextFramePts(buffer->timestamp());
if (next_frame_pts == kNoTimestamp()) {
// This can happen when emitting the very last buffer
// or if the stream do not meet the assumption behind |kHistorySize|.
DVLOG(LOG_LEVEL_ES) << "Using last frame duration: "
<< last_frame_duration_.InMilliseconds();
buffer->set_duration(last_frame_duration_);
} else {
base::TimeDelta duration = next_frame_pts - buffer->timestamp();
DVLOG(LOG_LEVEL_ES) << "Frame duration: " << duration.InMilliseconds();
buffer->set_duration(duration);
}
}
emitted_pts_.push_back(buffer->timestamp());
if (emitted_pts_.size() > kHistorySize)
emitted_pts_.pop_front();
last_frame_duration_ = buffer->duration();
emit_buffer_cb_.Run(buffer);
}
}
base::TimeDelta EsAdapterVideo::GetNextFramePts(base::TimeDelta current_pts) {
base::TimeDelta next_pts = kNoTimestamp();
// Consider the timestamps of future frames (in decode order).
// Note: the next frame is not enough when the GOP includes some B frames.
for (BufferQueue::const_iterator it = buffer_list_.begin();
it != buffer_list_.end(); ++it) {
if ((*it)->timestamp() < current_pts)
continue;
if (next_pts == kNoTimestamp() || next_pts > (*it)->timestamp())
next_pts = (*it)->timestamp();
}
// Consider the timestamps of previous frames (in decode order).
// In a simple GOP structure with B frames, the frame next to the last B
// frame (in presentation order) is located before in decode order.
for (std::list<base::TimeDelta>::const_iterator it = emitted_pts_.begin();
it != emitted_pts_.end(); ++it) {
if (*it < current_pts)
continue;
if (next_pts == kNoTimestamp() || next_pts > *it)
next_pts = *it;
}
return next_pts;
}
void EsAdapterVideo::ReplaceDiscardedFrames(
const scoped_refptr<StreamParserBuffer>& stream_parser_buffer) {
DCHECK(!discarded_frames_dts_.empty());
DCHECK(stream_parser_buffer->IsKeyframe());
// PTS is interpolated between the min PTS of discarded frames
// and the PTS of the first valid buffer.
base::TimeDelta pts = discarded_frames_min_pts_;
base::TimeDelta pts_delta =
(stream_parser_buffer->timestamp() - pts) / discarded_frames_dts_.size();
while (!discarded_frames_dts_.empty()) {
scoped_refptr<StreamParserBuffer> frame =
StreamParserBuffer::CopyFrom(
stream_parser_buffer->data(),
stream_parser_buffer->data_size(),
stream_parser_buffer->IsKeyframe(),
stream_parser_buffer->type(),
stream_parser_buffer->track_id());
frame->SetDecodeTimestamp(discarded_frames_dts_.front());
frame->set_timestamp(pts);
frame->set_duration(pts_delta);
buffer_list_.push_back(frame);
pts += pts_delta;
discarded_frames_dts_.pop_front();
}
}
} // namespace mp2t
} // namespace media
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