277 lines
8.7 KiB
C++
277 lines
8.7 KiB
C++
// 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_parser_adts.h"
|
|
|
|
#include <stdint.h>
|
|
|
|
#include <list>
|
|
|
|
#include "base/logging.h"
|
|
#include "base/strings/string_number_conversions.h"
|
|
#include "media/base/audio_timestamp_helper.h"
|
|
#include "media/base/bit_reader.h"
|
|
#include "media/base/media_sample.h"
|
|
#include "media/base/timestamp.h"
|
|
#include "media/formats/mp2t/adts_header.h"
|
|
#include "media/formats/mp2t/mp2t_common.h"
|
|
#include "media/formats/mpeg/adts_constants.h"
|
|
|
|
namespace edash_packager {
|
|
namespace media {
|
|
|
|
// Return true if buf corresponds to an ADTS syncword.
|
|
// |buf| size must be at least 2.
|
|
static bool isAdtsSyncWord(const uint8_t* buf) {
|
|
return (buf[0] == 0xff) && ((buf[1] & 0xf6) == 0xf0);
|
|
}
|
|
|
|
// Look for an ADTS syncword.
|
|
// |new_pos| returns
|
|
// - either the byte position of the ADTS frame (if found)
|
|
// - or the byte position of 1st byte that was not processed (if not found).
|
|
// In every case, the returned value in |new_pos| is such that new_pos >= pos
|
|
// |frame_sz| returns the size of the ADTS frame (if found).
|
|
// Return whether a syncword was found.
|
|
static bool LookForSyncWord(const uint8_t* raw_es,
|
|
int raw_es_size,
|
|
int pos,
|
|
int* new_pos,
|
|
int* frame_sz) {
|
|
DCHECK_GE(pos, 0);
|
|
DCHECK_LE(pos, raw_es_size);
|
|
|
|
int max_offset = raw_es_size - kAdtsHeaderMinSize;
|
|
if (pos >= max_offset) {
|
|
// Do not change the position if:
|
|
// - max_offset < 0: not enough bytes to get a full header
|
|
// Since pos >= 0, this is a subcase of the next condition.
|
|
// - pos >= max_offset: might be the case after reading one full frame,
|
|
// |pos| is then incremented by the frame size and might then point
|
|
// to the end of the buffer.
|
|
*new_pos = pos;
|
|
return false;
|
|
}
|
|
|
|
for (int offset = pos; offset < max_offset; offset++) {
|
|
const uint8_t* cur_buf = &raw_es[offset];
|
|
|
|
if (!isAdtsSyncWord(cur_buf))
|
|
// The first 12 bits must be 1.
|
|
// The layer field (2 bits) must be set to 0.
|
|
continue;
|
|
|
|
int frame_size =
|
|
mp2t::AdtsHeader::GetAdtsFrameSize(cur_buf, kAdtsHeaderMinSize);
|
|
if (frame_size < kAdtsHeaderMinSize) {
|
|
// Too short to be an ADTS frame.
|
|
continue;
|
|
}
|
|
|
|
// Check whether there is another frame
|
|
// |size| apart from the current one.
|
|
int remaining_size = raw_es_size - offset;
|
|
if (remaining_size >= frame_size + 2 &&
|
|
!isAdtsSyncWord(&cur_buf[frame_size])) {
|
|
continue;
|
|
}
|
|
|
|
*new_pos = offset;
|
|
*frame_sz = frame_size;
|
|
return true;
|
|
}
|
|
|
|
*new_pos = max_offset;
|
|
return false;
|
|
}
|
|
|
|
namespace mp2t {
|
|
|
|
EsParserAdts::EsParserAdts(uint32_t pid,
|
|
const NewStreamInfoCB& new_stream_info_cb,
|
|
const EmitSampleCB& emit_sample_cb,
|
|
bool sbr_in_mimetype)
|
|
: EsParser(pid),
|
|
new_stream_info_cb_(new_stream_info_cb),
|
|
emit_sample_cb_(emit_sample_cb),
|
|
sbr_in_mimetype_(sbr_in_mimetype) {
|
|
}
|
|
|
|
EsParserAdts::~EsParserAdts() {
|
|
}
|
|
|
|
bool EsParserAdts::Parse(const uint8_t* buf,
|
|
int size,
|
|
int64_t pts,
|
|
int64_t dts) {
|
|
int raw_es_size;
|
|
const uint8_t* raw_es;
|
|
|
|
// The incoming PTS applies to the access unit that comes just after
|
|
// the beginning of |buf|.
|
|
if (pts != kNoTimestamp) {
|
|
es_byte_queue_.Peek(&raw_es, &raw_es_size);
|
|
pts_list_.push_back(EsPts(raw_es_size, pts));
|
|
}
|
|
|
|
// Copy the input data to the ES buffer.
|
|
es_byte_queue_.Push(buf, size);
|
|
es_byte_queue_.Peek(&raw_es, &raw_es_size);
|
|
|
|
// Look for every ADTS frame in the ES buffer starting at offset = 0
|
|
int es_position = 0;
|
|
int frame_size;
|
|
while (LookForSyncWord(raw_es, raw_es_size, es_position,
|
|
&es_position, &frame_size)) {
|
|
const uint8_t* frame_ptr = raw_es + es_position;
|
|
DVLOG(LOG_LEVEL_ES)
|
|
<< "ADTS syncword @ pos=" << es_position
|
|
<< " frame_size=" << frame_size;
|
|
DVLOG(LOG_LEVEL_ES)
|
|
<< "ADTS header: "
|
|
<< base::HexEncode(frame_ptr, kAdtsHeaderMinSize);
|
|
|
|
// Do not process the frame if this one is a partial frame.
|
|
int remaining_size = raw_es_size - es_position;
|
|
if (frame_size > remaining_size)
|
|
break;
|
|
|
|
size_t header_size = AdtsHeader::GetAdtsHeaderSize(frame_ptr, frame_size);
|
|
|
|
// Update the audio configuration if needed.
|
|
DCHECK_GE(frame_size, kAdtsHeaderMinSize);
|
|
if (!UpdateAudioConfiguration(frame_ptr, frame_size))
|
|
return false;
|
|
|
|
// Get the PTS & the duration of this access unit.
|
|
while (!pts_list_.empty() &&
|
|
pts_list_.front().first <= es_position) {
|
|
audio_timestamp_helper_->SetBaseTimestamp(pts_list_.front().second);
|
|
pts_list_.pop_front();
|
|
}
|
|
|
|
int64_t current_pts = audio_timestamp_helper_->GetTimestamp();
|
|
int64_t frame_duration =
|
|
audio_timestamp_helper_->GetFrameDuration(kSamplesPerAACFrame);
|
|
|
|
// Emit an audio frame.
|
|
bool is_key_frame = true;
|
|
|
|
scoped_refptr<MediaSample> sample =
|
|
MediaSample::CopyFrom(
|
|
frame_ptr + header_size,
|
|
frame_size - header_size,
|
|
is_key_frame);
|
|
sample->set_pts(current_pts);
|
|
sample->set_dts(current_pts);
|
|
sample->set_duration(frame_duration);
|
|
emit_sample_cb_.Run(pid(), sample);
|
|
|
|
// Update the PTS of the next frame.
|
|
audio_timestamp_helper_->AddFrames(kSamplesPerAACFrame);
|
|
|
|
// Skip the current frame.
|
|
es_position += frame_size;
|
|
}
|
|
|
|
// Discard all the bytes that have been processed.
|
|
DiscardEs(es_position);
|
|
|
|
return true;
|
|
}
|
|
|
|
void EsParserAdts::Flush() {
|
|
}
|
|
|
|
void EsParserAdts::Reset() {
|
|
es_byte_queue_.Reset();
|
|
pts_list_.clear();
|
|
last_audio_decoder_config_ = scoped_refptr<AudioStreamInfo>();
|
|
}
|
|
|
|
bool EsParserAdts::UpdateAudioConfiguration(const uint8_t* adts_frame,
|
|
size_t adts_frame_size) {
|
|
const uint8_t kAacSampleSizeBits(16);
|
|
|
|
AdtsHeader adts_header;
|
|
if (!adts_header.Parse(adts_frame, adts_frame_size)) {
|
|
LOG(ERROR) << "Error parsing ADTS frame header.";
|
|
return false;
|
|
}
|
|
std::vector<uint8_t> audio_specific_config;
|
|
if (!adts_header.GetAudioSpecificConfig(&audio_specific_config))
|
|
return false;
|
|
|
|
if (last_audio_decoder_config_) {
|
|
// Verify that the audio decoder config has not changed.
|
|
if (last_audio_decoder_config_->extra_data() == audio_specific_config) {
|
|
// Audio configuration has not changed.
|
|
return true;
|
|
}
|
|
NOTIMPLEMENTED() << "Varying audio configurations are not supported.";
|
|
return false;
|
|
}
|
|
|
|
// The following code is written according to ISO 14496 Part 3 Table 1.11 and
|
|
// Table 1.22. (Table 1.11 refers to the capping to 48000, Table 1.22 refers
|
|
// to SBR doubling the AAC sample rate.)
|
|
int samples_per_second = adts_header.GetSamplingFrequency();
|
|
int extended_samples_per_second = sbr_in_mimetype_
|
|
? std::min(2 * samples_per_second, 48000)
|
|
: samples_per_second;
|
|
|
|
last_audio_decoder_config_ = scoped_refptr<StreamInfo>(
|
|
new AudioStreamInfo(
|
|
pid(),
|
|
kMpeg2Timescale,
|
|
kInfiniteDuration,
|
|
kCodecAAC,
|
|
AudioStreamInfo::GetCodecString(kCodecAAC,
|
|
adts_header.GetObjectType()),
|
|
std::string(),
|
|
kAacSampleSizeBits,
|
|
adts_header.GetNumChannels(),
|
|
extended_samples_per_second,
|
|
audio_specific_config.data(),
|
|
audio_specific_config.size(),
|
|
false));
|
|
|
|
DVLOG(1) << "Sampling frequency: " << samples_per_second;
|
|
DVLOG(1) << "Extended sampling frequency: " << extended_samples_per_second;
|
|
DVLOG(1) << "Channel config: " << adts_header.GetNumChannels();
|
|
DVLOG(1) << "Object type: " << adts_header.GetObjectType();
|
|
// Reset the timestamp helper to use a new sampling frequency.
|
|
if (audio_timestamp_helper_) {
|
|
int64_t base_timestamp = audio_timestamp_helper_->GetTimestamp();
|
|
audio_timestamp_helper_.reset(
|
|
new AudioTimestampHelper(kMpeg2Timescale, samples_per_second));
|
|
audio_timestamp_helper_->SetBaseTimestamp(base_timestamp);
|
|
} else {
|
|
audio_timestamp_helper_.reset(
|
|
new AudioTimestampHelper(kMpeg2Timescale, extended_samples_per_second));
|
|
}
|
|
|
|
// Audio config notification.
|
|
new_stream_info_cb_.Run(last_audio_decoder_config_);
|
|
|
|
return true;
|
|
}
|
|
|
|
void EsParserAdts::DiscardEs(int nbytes) {
|
|
DCHECK_GE(nbytes, 0);
|
|
if (nbytes <= 0)
|
|
return;
|
|
|
|
// Adjust the ES position of each PTS.
|
|
for (EsPtsList::iterator it = pts_list_.begin(); it != pts_list_.end(); ++it)
|
|
it->first -= nbytes;
|
|
|
|
// Discard |nbytes| of ES.
|
|
es_byte_queue_.Pop(nbytes);
|
|
}
|
|
|
|
} // namespace mp2t
|
|
} // namespace media
|
|
} // namespace edash_packager
|