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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/filters/source_buffer_range.h"
#include <algorithm>
#include "media/base/timestamp_constants.h"
namespace media {
// Comparison operators for std::upper_bound() and std::lower_bound().
static bool CompareTimeDeltaToStreamParserBuffer(
const DecodeTimestamp& decode_timestamp,
const scoped_refptr<StreamParserBuffer>& buffer) {
return decode_timestamp < buffer->GetDecodeTimestamp();
}
static bool CompareStreamParserBufferToTimeDelta(
const scoped_refptr<StreamParserBuffer>& buffer,
const DecodeTimestamp& decode_timestamp) {
return buffer->GetDecodeTimestamp() < decode_timestamp;
}
bool SourceBufferRange::IsUncommonSameTimestampSequence(
bool prev_is_keyframe,
bool current_is_keyframe) {
return current_is_keyframe && !prev_is_keyframe;
}
SourceBufferRange::SourceBufferRange(
GapPolicy gap_policy,
const BufferQueue& new_buffers,
DecodeTimestamp range_start_time,
const InterbufferDistanceCB& interbuffer_distance_cb)
: gap_policy_(gap_policy),
keyframe_map_index_base_(0),
next_buffer_index_(-1),
range_start_time_(range_start_time),
interbuffer_distance_cb_(interbuffer_distance_cb),
size_in_bytes_(0) {
CHECK(!new_buffers.empty());
DCHECK(new_buffers.front()->is_key_frame());
DCHECK(!interbuffer_distance_cb.is_null());
AppendBuffersToEnd(new_buffers, range_start_time_);
}
SourceBufferRange::~SourceBufferRange() {}
void SourceBufferRange::AppendBuffersToEnd(
const BufferQueue& new_buffers,
DecodeTimestamp new_buffers_group_start_timestamp) {
CHECK(buffers_.empty() ||
CanAppendBuffersToEnd(new_buffers, new_buffers_group_start_timestamp));
DCHECK(range_start_time_ == kNoDecodeTimestamp() ||
range_start_time_ <= new_buffers.front()->GetDecodeTimestamp());
AdjustEstimatedDurationForNewAppend(new_buffers);
for (BufferQueue::const_iterator itr = new_buffers.begin();
itr != new_buffers.end();
++itr) {
DCHECK((*itr)->GetDecodeTimestamp() != kNoDecodeTimestamp());
buffers_.push_back(*itr);
size_in_bytes_ += (*itr)->data_size();
if ((*itr)->is_key_frame()) {
keyframe_map_.insert(
std::make_pair((*itr)->GetDecodeTimestamp(),
buffers_.size() - 1 + keyframe_map_index_base_));
}
}
}
void SourceBufferRange::AdjustEstimatedDurationForNewAppend(
const BufferQueue& new_buffers) {
if (buffers_.empty() || new_buffers.empty()) {
return;
}
// If the last of the previously appended buffers contains estimated duration,
// we now refine that estimate by taking the PTS delta from the first new
// buffer being appended.
const auto& last_appended_buffer = buffers_.back();
if (last_appended_buffer->is_duration_estimated()) {
base::TimeDelta timestamp_delta =
new_buffers.front()->timestamp() - last_appended_buffer->timestamp();
DCHECK(timestamp_delta > base::TimeDelta());
if (last_appended_buffer->duration() != timestamp_delta) {
DVLOG(1) << "Replacing estimated duration ("
<< last_appended_buffer->duration()
<< ") from previous range-end with derived duration ("
<< timestamp_delta << ").";
last_appended_buffer->set_duration(timestamp_delta);
}
}
}
void SourceBufferRange::Seek(DecodeTimestamp timestamp) {
DCHECK(CanSeekTo(timestamp));
DCHECK(!keyframe_map_.empty());
KeyframeMap::iterator result = GetFirstKeyframeAtOrBefore(timestamp);
next_buffer_index_ = result->second - keyframe_map_index_base_;
CHECK_LT(next_buffer_index_, static_cast<int>(buffers_.size()))
<< next_buffer_index_ << ", size = " << buffers_.size();
}
void SourceBufferRange::SeekAheadTo(DecodeTimestamp timestamp) {
SeekAhead(timestamp, false);
}
void SourceBufferRange::SeekAheadPast(DecodeTimestamp timestamp) {
SeekAhead(timestamp, true);
}
void SourceBufferRange::SeekAhead(DecodeTimestamp timestamp,
bool skip_given_timestamp) {
DCHECK(!keyframe_map_.empty());
KeyframeMap::iterator result =
GetFirstKeyframeAt(timestamp, skip_given_timestamp);
// If there isn't a keyframe after |timestamp|, then seek to end and return
// kNoTimestamp to signal such.
if (result == keyframe_map_.end()) {
next_buffer_index_ = -1;
return;
}
next_buffer_index_ = result->second - keyframe_map_index_base_;
DCHECK_LT(next_buffer_index_, static_cast<int>(buffers_.size()));
}
void SourceBufferRange::SeekToStart() {
CHECK(!buffers_.empty());
next_buffer_index_ = 0;
}
SourceBufferRange* SourceBufferRange::SplitRange(DecodeTimestamp timestamp) {
CHECK(!buffers_.empty());
// Find the first keyframe at or after |timestamp|.
KeyframeMap::iterator new_beginning_keyframe =
GetFirstKeyframeAt(timestamp, false);
// If there is no keyframe after |timestamp|, we can't split the range.
if (new_beginning_keyframe == keyframe_map_.end())
return NULL;
// Remove the data beginning at |keyframe_index| from |buffers_| and save it
// into |removed_buffers|.
int keyframe_index =
new_beginning_keyframe->second - keyframe_map_index_base_;
DCHECK_LT(keyframe_index, static_cast<int>(buffers_.size()));
BufferQueue::iterator starting_point = buffers_.begin() + keyframe_index;
BufferQueue removed_buffers(starting_point, buffers_.end());
DecodeTimestamp new_range_start_timestamp = kNoDecodeTimestamp();
if (GetStartTimestamp() < buffers_.front()->GetDecodeTimestamp() &&
timestamp < removed_buffers.front()->GetDecodeTimestamp()) {
// The split is in the gap between |range_start_time_| and the first buffer
// of the new range so we should set the start time of the new range to
// |timestamp| so we preserve part of the gap in the new range.
new_range_start_timestamp = timestamp;
}
keyframe_map_.erase(new_beginning_keyframe, keyframe_map_.end());
FreeBufferRange(starting_point, buffers_.end());
// Create a new range with |removed_buffers|.
SourceBufferRange* split_range =
new SourceBufferRange(
gap_policy_, removed_buffers, new_range_start_timestamp,
interbuffer_distance_cb_);
// If the next buffer position is now in |split_range|, update the state of
// this range and |split_range| accordingly.
if (next_buffer_index_ >= static_cast<int>(buffers_.size())) {
split_range->next_buffer_index_ = next_buffer_index_ - keyframe_index;
int split_range_next_buffer_index = split_range->next_buffer_index_;
CHECK_GE(split_range_next_buffer_index, 0);
// Note that a SourceBufferRange's |next_buffer_index_| can be the index
// of a buffer one beyond what is currently in |buffers_|.
CHECK_LE(split_range_next_buffer_index,
static_cast<int>(split_range->buffers_.size()));
ResetNextBufferPosition();
}
return split_range;
}
SourceBufferRange::BufferQueue::iterator SourceBufferRange::GetBufferItrAt(
DecodeTimestamp timestamp,
bool skip_given_timestamp) {
return skip_given_timestamp
? std::upper_bound(buffers_.begin(),
buffers_.end(),
timestamp,
CompareTimeDeltaToStreamParserBuffer)
: std::lower_bound(buffers_.begin(),
buffers_.end(),
timestamp,
CompareStreamParserBufferToTimeDelta);
}
SourceBufferRange::KeyframeMap::iterator
SourceBufferRange::GetFirstKeyframeAt(DecodeTimestamp timestamp,
bool skip_given_timestamp) {
return skip_given_timestamp ?
keyframe_map_.upper_bound(timestamp) :
keyframe_map_.lower_bound(timestamp);
}
SourceBufferRange::KeyframeMap::iterator
SourceBufferRange::GetFirstKeyframeAtOrBefore(DecodeTimestamp timestamp) {
KeyframeMap::iterator result = keyframe_map_.lower_bound(timestamp);
// lower_bound() returns the first element >= |timestamp|, so we want the
// previous element if it did not return the element exactly equal to
// |timestamp|.
if (result != keyframe_map_.begin() &&
(result == keyframe_map_.end() || result->first != timestamp)) {
--result;
}
return result;
}
void SourceBufferRange::DeleteAll(BufferQueue* removed_buffers) {
TruncateAt(buffers_.begin(), removed_buffers);
}
bool SourceBufferRange::TruncateAt(
DecodeTimestamp timestamp, BufferQueue* removed_buffers,
bool is_exclusive) {
// Find the place in |buffers_| where we will begin deleting data.
BufferQueue::iterator starting_point =
GetBufferItrAt(timestamp, is_exclusive);
return TruncateAt(starting_point, removed_buffers);
}
size_t SourceBufferRange::DeleteGOPFromFront(BufferQueue* deleted_buffers) {
DCHECK(!buffers_.empty());
DCHECK(!FirstGOPContainsNextBufferPosition());
DCHECK(deleted_buffers);
int buffers_deleted = 0;
size_t total_bytes_deleted = 0;
KeyframeMap::iterator front = keyframe_map_.begin();
DCHECK(front != keyframe_map_.end());
// Delete the keyframe at the start of |keyframe_map_|.
keyframe_map_.erase(front);
// Now we need to delete all the buffers that depend on the keyframe we've
// just deleted.
int end_index = keyframe_map_.size() > 0 ?
keyframe_map_.begin()->second - keyframe_map_index_base_ :
buffers_.size();
// Delete buffers from the beginning of the buffered range up until (but not
// including) the next keyframe.
for (int i = 0; i < end_index; i++) {
size_t bytes_deleted = buffers_.front()->data_size();
DCHECK_GE(size_in_bytes_, bytes_deleted);
size_in_bytes_ -= bytes_deleted;
total_bytes_deleted += bytes_deleted;
deleted_buffers->push_back(buffers_.front());
buffers_.pop_front();
++buffers_deleted;
}
// Update |keyframe_map_index_base_| to account for the deleted buffers.
keyframe_map_index_base_ += buffers_deleted;
if (next_buffer_index_ > -1) {
next_buffer_index_ -= buffers_deleted;
CHECK_GE(next_buffer_index_, 0) << next_buffer_index_ << ", deleted "
<< buffers_deleted;
}
// Invalidate range start time if we've deleted the first buffer of the range.
if (buffers_deleted > 0)
range_start_time_ = kNoDecodeTimestamp();
return total_bytes_deleted;
}
size_t SourceBufferRange::DeleteGOPFromBack(BufferQueue* deleted_buffers) {
DCHECK(!buffers_.empty());
DCHECK(!LastGOPContainsNextBufferPosition());
DCHECK(deleted_buffers);
// Remove the last GOP's keyframe from the |keyframe_map_|.
KeyframeMap::iterator back = keyframe_map_.end();
DCHECK_GT(keyframe_map_.size(), 0u);
--back;
// The index of the first buffer in the last GOP is equal to the new size of
// |buffers_| after that GOP is deleted.
size_t goal_size = back->second - keyframe_map_index_base_;
keyframe_map_.erase(back);
size_t total_bytes_deleted = 0;
while (buffers_.size() != goal_size) {
size_t bytes_deleted = buffers_.back()->data_size();
DCHECK_GE(size_in_bytes_, bytes_deleted);
size_in_bytes_ -= bytes_deleted;
total_bytes_deleted += bytes_deleted;
// We're removing buffers from the back, so push each removed buffer to the
// front of |deleted_buffers| so that |deleted_buffers| are in nondecreasing
// order.
deleted_buffers->push_front(buffers_.back());
buffers_.pop_back();
}
return total_bytes_deleted;
}
size_t SourceBufferRange::GetRemovalGOP(
DecodeTimestamp start_timestamp, DecodeTimestamp end_timestamp,
size_t total_bytes_to_free, DecodeTimestamp* removal_end_timestamp) {
size_t bytes_removed = 0;
KeyframeMap::iterator gop_itr = GetFirstKeyframeAt(start_timestamp, false);
if (gop_itr == keyframe_map_.end())
return 0;
int keyframe_index = gop_itr->second - keyframe_map_index_base_;
BufferQueue::iterator buffer_itr = buffers_.begin() + keyframe_index;
KeyframeMap::iterator gop_end = keyframe_map_.end();
if (end_timestamp < GetBufferedEndTimestamp())
gop_end = GetFirstKeyframeAtOrBefore(end_timestamp);
// Check if the removal range is within a GOP and skip the loop if so.
// [keyframe]...[start_timestamp]...[end_timestamp]...[keyframe]
KeyframeMap::iterator gop_itr_prev = gop_itr;
if (gop_itr_prev != keyframe_map_.begin() && --gop_itr_prev == gop_end)
gop_end = gop_itr;
while (gop_itr != gop_end && bytes_removed < total_bytes_to_free) {
++gop_itr;
size_t gop_size = 0;
int next_gop_index = gop_itr == keyframe_map_.end() ?
buffers_.size() : gop_itr->second - keyframe_map_index_base_;
BufferQueue::iterator next_gop_start = buffers_.begin() + next_gop_index;
for (; buffer_itr != next_gop_start; ++buffer_itr) {
gop_size += (*buffer_itr)->data_size();
}
bytes_removed += gop_size;
}
if (bytes_removed > 0) {
*removal_end_timestamp = gop_itr == keyframe_map_.end() ?
GetBufferedEndTimestamp() : gop_itr->first;
}
return bytes_removed;
}
bool SourceBufferRange::FirstGOPEarlierThanMediaTime(
DecodeTimestamp media_time) const {
if (keyframe_map_.size() == 1u)
return (GetBufferedEndTimestamp() <= media_time);
KeyframeMap::const_iterator second_gop = keyframe_map_.begin();
++second_gop;
return second_gop->first <= media_time;
}
bool SourceBufferRange::FirstGOPContainsNextBufferPosition() const {
if (!HasNextBufferPosition())
return false;
// If there is only one GOP, it must contain the next buffer position.
if (keyframe_map_.size() == 1u)
return true;
KeyframeMap::const_iterator second_gop = keyframe_map_.begin();
++second_gop;
return next_buffer_index_ < second_gop->second - keyframe_map_index_base_;
}
bool SourceBufferRange::LastGOPContainsNextBufferPosition() const {
if (!HasNextBufferPosition())
return false;
// If there is only one GOP, it must contain the next buffer position.
if (keyframe_map_.size() == 1u)
return true;
KeyframeMap::const_iterator last_gop = keyframe_map_.end();
--last_gop;
return last_gop->second - keyframe_map_index_base_ <= next_buffer_index_;
}
void SourceBufferRange::FreeBufferRange(
const BufferQueue::iterator& starting_point,
const BufferQueue::iterator& ending_point) {
for (BufferQueue::iterator itr = starting_point;
itr != ending_point; ++itr) {
size_t itr_data_size = static_cast<size_t>((*itr)->data_size());
DCHECK_GE(size_in_bytes_, itr_data_size);
size_in_bytes_ -= itr_data_size;
}
buffers_.erase(starting_point, ending_point);
}
bool SourceBufferRange::TruncateAt(
const BufferQueue::iterator& starting_point, BufferQueue* removed_buffers) {
DCHECK(!removed_buffers || removed_buffers->empty());
// Return if we're not deleting anything.
if (starting_point == buffers_.end())
return buffers_.empty();
// Reset the next buffer index if we will be deleting the buffer that's next
// in sequence.
if (HasNextBufferPosition()) {
DecodeTimestamp next_buffer_timestamp = GetNextTimestamp();
if (next_buffer_timestamp == kNoDecodeTimestamp() ||
next_buffer_timestamp >= (*starting_point)->GetDecodeTimestamp()) {
if (HasNextBuffer() && removed_buffers) {
int starting_offset = starting_point - buffers_.begin();
int next_buffer_offset = next_buffer_index_ - starting_offset;
DCHECK_GE(next_buffer_offset, 0);
BufferQueue saved(starting_point + next_buffer_offset, buffers_.end());
removed_buffers->swap(saved);
}
ResetNextBufferPosition();
}
}
// Remove keyframes from |starting_point| onward.
KeyframeMap::iterator starting_point_keyframe =
keyframe_map_.lower_bound((*starting_point)->GetDecodeTimestamp());
keyframe_map_.erase(starting_point_keyframe, keyframe_map_.end());
// Remove everything from |starting_point| onward.
FreeBufferRange(starting_point, buffers_.end());
return buffers_.empty();
}
bool SourceBufferRange::GetNextBuffer(
scoped_refptr<StreamParserBuffer>* out_buffer) {
if (!HasNextBuffer())
return false;
*out_buffer = buffers_[next_buffer_index_];
next_buffer_index_++;
return true;
}
bool SourceBufferRange::HasNextBuffer() const {
return next_buffer_index_ >= 0 &&
next_buffer_index_ < static_cast<int>(buffers_.size());
}
int SourceBufferRange::GetNextConfigId() const {
CHECK(HasNextBuffer()) << next_buffer_index_;
// If the next buffer is an audio splice frame, the next effective config id
// comes from the first fade out preroll buffer.
return buffers_[next_buffer_index_]->GetSpliceBufferConfigId(0);
}
DecodeTimestamp SourceBufferRange::GetNextTimestamp() const {
CHECK(!buffers_.empty()) << next_buffer_index_;
CHECK(HasNextBufferPosition()) << next_buffer_index_
<< ", size=" << buffers_.size();
if (next_buffer_index_ >= static_cast<int>(buffers_.size())) {
return kNoDecodeTimestamp();
}
return buffers_[next_buffer_index_]->GetDecodeTimestamp();
}
bool SourceBufferRange::HasNextBufferPosition() const {
return next_buffer_index_ >= 0;
}
void SourceBufferRange::ResetNextBufferPosition() {
next_buffer_index_ = -1;
}
void SourceBufferRange::AppendRangeToEnd(const SourceBufferRange& range,
bool transfer_current_position) {
DCHECK(CanAppendRangeToEnd(range));
DCHECK(!buffers_.empty());
if (transfer_current_position && range.next_buffer_index_ >= 0)
next_buffer_index_ = range.next_buffer_index_ + buffers_.size();
AppendBuffersToEnd(range.buffers_, kNoDecodeTimestamp());
}
bool SourceBufferRange::CanAppendRangeToEnd(
const SourceBufferRange& range) const {
return CanAppendBuffersToEnd(range.buffers_, kNoDecodeTimestamp());
}
bool SourceBufferRange::CanAppendBuffersToEnd(
const BufferQueue& buffers,
DecodeTimestamp new_buffers_group_start_timestamp) const {
DCHECK(!buffers_.empty());
if (new_buffers_group_start_timestamp == kNoDecodeTimestamp()) {
return IsNextInSequence(buffers.front()->GetDecodeTimestamp());
}
DCHECK(new_buffers_group_start_timestamp >= GetEndTimestamp());
DCHECK(buffers.front()->GetDecodeTimestamp() >=
new_buffers_group_start_timestamp);
return IsNextInSequence(new_buffers_group_start_timestamp);
}
bool SourceBufferRange::BelongsToRange(DecodeTimestamp timestamp) const {
DCHECK(!buffers_.empty());
return (IsNextInSequence(timestamp) ||
(GetStartTimestamp() <= timestamp && timestamp <= GetEndTimestamp()));
}
bool SourceBufferRange::CanSeekTo(DecodeTimestamp timestamp) const {
DecodeTimestamp start_timestamp =
std::max(DecodeTimestamp(), GetStartTimestamp() - GetFudgeRoom());
return !keyframe_map_.empty() && start_timestamp <= timestamp &&
timestamp < GetBufferedEndTimestamp();
}
bool SourceBufferRange::CompletelyOverlaps(
const SourceBufferRange& range) const {
return GetStartTimestamp() <= range.GetStartTimestamp() &&
GetEndTimestamp() >= range.GetEndTimestamp();
}
bool SourceBufferRange::EndOverlaps(const SourceBufferRange& range) const {
return range.GetStartTimestamp() <= GetEndTimestamp() &&
GetEndTimestamp() < range.GetEndTimestamp();
}
DecodeTimestamp SourceBufferRange::GetStartTimestamp() const {
DCHECK(!buffers_.empty());
DecodeTimestamp start_timestamp = range_start_time_;
if (start_timestamp == kNoDecodeTimestamp())
start_timestamp = buffers_.front()->GetDecodeTimestamp();
return start_timestamp;
}
DecodeTimestamp SourceBufferRange::GetEndTimestamp() const {
DCHECK(!buffers_.empty());
return buffers_.back()->GetDecodeTimestamp();
}
DecodeTimestamp SourceBufferRange::GetBufferedEndTimestamp() const {
DCHECK(!buffers_.empty());
base::TimeDelta duration = buffers_.back()->duration();
if (duration == kNoTimestamp() || duration == base::TimeDelta())
duration = GetApproximateDuration();
return GetEndTimestamp() + duration;
}
DecodeTimestamp SourceBufferRange::NextKeyframeTimestamp(
DecodeTimestamp timestamp) {
DCHECK(!keyframe_map_.empty());
if (timestamp < GetStartTimestamp() || timestamp >= GetBufferedEndTimestamp())
return kNoDecodeTimestamp();
KeyframeMap::iterator itr = GetFirstKeyframeAt(timestamp, false);
if (itr == keyframe_map_.end())
return kNoDecodeTimestamp();
// If the timestamp is inside the gap between the start of the coded frame
// group and the first buffer, then just pretend there is a keyframe at the
// specified timestamp.
if (itr == keyframe_map_.begin() && timestamp > range_start_time_ &&
timestamp < itr->first) {
return timestamp;
}
return itr->first;
}
DecodeTimestamp SourceBufferRange::KeyframeBeforeTimestamp(
DecodeTimestamp timestamp) {
DCHECK(!keyframe_map_.empty());
if (timestamp < GetStartTimestamp() || timestamp >= GetBufferedEndTimestamp())
return kNoDecodeTimestamp();
return GetFirstKeyframeAtOrBefore(timestamp)->first;
}
bool SourceBufferRange::IsNextInSequence(DecodeTimestamp timestamp) const {
DecodeTimestamp end = buffers_.back()->GetDecodeTimestamp();
return (end == timestamp ||
(end < timestamp &&
(gap_policy_ == ALLOW_GAPS || timestamp <= end + GetFudgeRoom())));
}
base::TimeDelta SourceBufferRange::GetFudgeRoom() const {
// Because we do not know exactly when is the next timestamp, any buffer
// that starts within 2x the approximate duration of a buffer is considered
// within this range.
return 2 * GetApproximateDuration();
}
base::TimeDelta SourceBufferRange::GetApproximateDuration() const {
base::TimeDelta max_interbuffer_distance = interbuffer_distance_cb_.Run();
DCHECK(max_interbuffer_distance != kNoTimestamp());
return max_interbuffer_distance;
}
bool SourceBufferRange::GetBuffersInRange(DecodeTimestamp start,
DecodeTimestamp end,
BufferQueue* buffers) {
// Find the nearest buffer with a decode timestamp <= start.
const DecodeTimestamp first_timestamp = KeyframeBeforeTimestamp(start);
if (first_timestamp == kNoDecodeTimestamp())
return false;
// Find all buffers involved in the range.
const size_t previous_size = buffers->size();
for (BufferQueue::iterator it = GetBufferItrAt(first_timestamp, false);
it != buffers_.end();
++it) {
const scoped_refptr<StreamParserBuffer>& buffer = *it;
// Buffers without duration are not supported, so bail if we encounter any.
if (buffer->duration() == kNoTimestamp() ||
buffer->duration() <= base::TimeDelta()) {
return false;
}
if (buffer->end_of_stream() ||
buffer->timestamp() >= end.ToPresentationTime()) {
break;
}
if (buffer->timestamp() + buffer->duration() <= start.ToPresentationTime())
continue;
buffers->push_back(buffer);
}
return previous_size < buffers->size();
}
} // namespace media
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