diff options
Diffstat (limited to 'chromium/media/mp3/mp3_stream_parser.cc')
| -rw-r--r-- | chromium/media/mp3/mp3_stream_parser.cc | 598 |
1 files changed, 598 insertions, 0 deletions
diff --git a/chromium/media/mp3/mp3_stream_parser.cc b/chromium/media/mp3/mp3_stream_parser.cc new file mode 100644 index 00000000000..0688d99fcc9 --- /dev/null +++ b/chromium/media/mp3/mp3_stream_parser.cc @@ -0,0 +1,598 @@ +// Copyright 2013 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/mp3/mp3_stream_parser.h" + +#include "base/bind.h" +#include "base/callback_helpers.h" +#include "base/message_loop/message_loop.h" +#include "media/base/bit_reader.h" +#include "media/base/buffers.h" +#include "media/base/stream_parser_buffer.h" +#include "media/base/video_decoder_config.h" +#include "net/http/http_util.h" + +namespace media { + +static const uint32 kMP3StartCodeMask = 0xffe00000; +static const uint32 kICYStartCode = 0x49435920; // 'ICY ' + +// Arbitrary upper bound on the size of an IceCast header before it +// triggers an error. +static const int kMaxIcecastHeaderSize = 4096; + +static const uint32 kID3StartCodeMask = 0xffffff00; +static const uint32 kID3v1StartCode = 0x54414700; // 'TAG\0' +static const int kID3v1Size = 128; +static const int kID3v1ExtendedSize = 227; +static const uint32 kID3v2StartCode = 0x49443300; // 'ID3\0' + +// Map that determines which bitrate_index & channel_mode combinations +// are allowed. +// Derived from: http://mpgedit.org/mpgedit/mpeg_format/MP3Format.html +static const bool kIsAllowed[17][4] = { + { true, true, true, true }, // free + { true, false, false, false }, // 32 + { true, false, false, false }, // 48 + { true, false, false, false }, // 56 + { true, true, true, true }, // 64 + { true, false, false, false }, // 80 + { true, true, true, true }, // 96 + { true, true, true, true }, // 112 + { true, true, true, true }, // 128 + { true, true, true, true }, // 160 + { true, true, true, true }, // 192 + { false, true, true, true }, // 224 + { false, true, true, true }, // 256 + { false, true, true, true }, // 320 + { false, true, true, true }, // 384 + { false, false, false, false } // bad +}; + +// Maps version and layer information in the frame header +// into an index for the |kBitrateMap|. +// Derived from: http://mpgedit.org/mpgedit/mpeg_format/MP3Format.html +static const int kVersionLayerMap[4][4] = { + // { reserved, L3, L2, L1 } + { 5, 4, 4, 3 }, // MPEG 2.5 + { 5, 5, 5, 5 }, // reserved + { 5, 4, 4, 3 }, // MPEG 2 + { 5, 2, 1, 0 } // MPEG 1 +}; + +// Maps the bitrate index field in the header and an index +// from |kVersionLayerMap| to a frame bitrate. +// Derived from: http://mpgedit.org/mpgedit/mpeg_format/MP3Format.html +static const int kBitrateMap[16][6] = { + // { V1L1, V1L2, V1L3, V2L1, V2L2 & V2L3, reserved } + { 0, 0, 0, 0, 0, 0 }, + { 32, 32, 32, 32, 8, 0 }, + { 64, 48, 40, 48, 16, 0 }, + { 96, 56, 48, 56, 24, 0 }, + { 128, 64, 56, 64, 32, 0 }, + { 160, 80, 64, 80, 40, 0 }, + { 192, 96, 80, 96, 48, 0 }, + { 224, 112, 96, 112, 56, 0 }, + { 256, 128, 112, 128, 64, 0 }, + { 288, 160, 128, 144, 80, 0 }, + { 320, 192, 160, 160, 96, 0 }, + { 352, 224, 192, 176, 112, 0 }, + { 384, 256, 224, 192, 128, 0 }, + { 416, 320, 256, 224, 144, 0 }, + { 448, 384, 320, 256, 160, 0 }, + { 0, 0, 0, 0, 0} +}; + +// Maps the sample rate index and version fields from the frame header +// to a sample rate. +// Derived from: http://mpgedit.org/mpgedit/mpeg_format/MP3Format.html +static const int kSampleRateMap[4][4] = { + // { V2.5, reserved, V2, V1 } + { 11025, 0, 22050, 44100 }, + { 12000, 0, 24000, 48000 }, + { 8000, 0, 16000, 32000 }, + { 0, 0, 0, 0 } +}; + +// Frame header field constants. +static const int kVersion1 = 3; +static const int kVersion2 = 2; +static const int kVersionReserved = 1; +static const int kVersion2_5 = 0; +static const int kLayerReserved = 0; +static const int kLayer1 = 3; +static const int kLayer2 = 2; +static const int kLayer3 = 1; +static const int kBitrateFree = 0; +static const int kBitrateBad = 0xf; +static const int kSampleRateReserved = 3; + +MP3StreamParser::MP3StreamParser() + : state_(UNINITIALIZED), + in_media_segment_(false) { +} + +MP3StreamParser::~MP3StreamParser() {} + +void MP3StreamParser::Init(const InitCB& init_cb, + const NewConfigCB& config_cb, + const NewBuffersCB& new_buffers_cb, + const NewTextBuffersCB& text_cb, + const NeedKeyCB& need_key_cb, + const AddTextTrackCB& add_text_track_cb, + const NewMediaSegmentCB& new_segment_cb, + const base::Closure& end_of_segment_cb, + const LogCB& log_cb) { + DVLOG(1) << __FUNCTION__; + DCHECK_EQ(state_, UNINITIALIZED); + init_cb_ = init_cb; + config_cb_ = config_cb; + new_buffers_cb_ = new_buffers_cb; + new_segment_cb_ = new_segment_cb; + end_of_segment_cb_ = end_of_segment_cb; + log_cb_ = log_cb; + + ChangeState(INITIALIZED); +} + +void MP3StreamParser::Flush() { + DVLOG(1) << __FUNCTION__; + DCHECK_NE(state_, UNINITIALIZED); + queue_.Reset(); + timestamp_helper_->SetBaseTimestamp(base::TimeDelta()); + in_media_segment_ = false; +} + +bool MP3StreamParser::Parse(const uint8* buf, int size) { + DVLOG(1) << __FUNCTION__ << "(" << size << ")"; + DCHECK(buf); + DCHECK_GT(size, 0); + DCHECK_NE(state_, UNINITIALIZED); + + if (state_ == PARSE_ERROR) + return false; + + DCHECK_EQ(state_, INITIALIZED); + + queue_.Push(buf, size); + + bool end_of_segment = true; + BufferQueue buffers; + for (;;) { + const uint8* data; + int data_size; + queue_.Peek(&data, &data_size); + + if (size < 4) + break; + + uint32 start_code = data[0] << 24 | data[1] << 16 | data[2] << 8 | data[3]; + int bytes_read = 0; + bool parsed_metadata = true; + if ((start_code & kMP3StartCodeMask) == kMP3StartCodeMask) { + bytes_read = ParseMP3Frame(data, data_size, &buffers); + + // Only allow the current segment to end if a full frame has been parsed. + end_of_segment = bytes_read > 0; + parsed_metadata = false; + } else if (start_code == kICYStartCode) { + bytes_read = ParseIcecastHeader(data, data_size); + } else if ((start_code & kID3StartCodeMask) == kID3v1StartCode) { + bytes_read = ParseID3v1(data, data_size); + } else if ((start_code & kID3StartCodeMask) == kID3v2StartCode) { + bytes_read = ParseID3v2(data, data_size); + } else { + bytes_read = FindNextValidStartCode(data, data_size); + + if (bytes_read > 0) { + DVLOG(1) << "Unexpected start code 0x" << std::hex << start_code; + DVLOG(1) << "SKIPPING " << bytes_read << " bytes of garbage."; + } + } + + CHECK_LE(bytes_read, data_size); + + if (bytes_read < 0) { + ChangeState(PARSE_ERROR); + return false; + } else if (bytes_read == 0) { + // Need more data. + break; + } + + // Send pending buffers if we have encountered metadata. + if (parsed_metadata && !buffers.empty() && !SendBuffers(&buffers, true)) + return false; + + queue_.Pop(bytes_read); + end_of_segment = true; + } + + if (buffers.empty()) + return true; + + // Send buffers collected in this append that haven't been sent yet. + return SendBuffers(&buffers, end_of_segment); +} + +void MP3StreamParser::ChangeState(State state) { + DVLOG(1) << __FUNCTION__ << "() : " << state_ << " -> " << state; + state_ = state; +} + +int MP3StreamParser::ParseFrameHeader(const uint8* data, int size, + int* frame_size, + int* sample_rate, + ChannelLayout* channel_layout, + int* sample_count) const { + DCHECK(data); + DCHECK_GE(size, 0); + DCHECK(frame_size); + + if (size < 4) + return 0; + + BitReader reader(data, size); + int sync; + int version; + int layer; + int is_protected; + int bitrate_index; + int sample_rate_index; + int has_padding; + int is_private; + int channel_mode; + int other_flags; + + if (!reader.ReadBits(11, &sync) || + !reader.ReadBits(2, &version) || + !reader.ReadBits(2, &layer) || + !reader.ReadBits(1, &is_protected) || + !reader.ReadBits(4, &bitrate_index) || + !reader.ReadBits(2, &sample_rate_index) || + !reader.ReadBits(1, &has_padding) || + !reader.ReadBits(1, &is_private) || + !reader.ReadBits(2, &channel_mode) || + !reader.ReadBits(6, &other_flags)) { + return -1; + } + + DVLOG(2) << "Header data :" << std::hex + << " sync 0x" << sync + << " version 0x" << version + << " layer 0x" << layer + << " bitrate_index 0x" << bitrate_index + << " sample_rate_index 0x" << sample_rate_index + << " channel_mode 0x" << channel_mode; + + if (sync != 0x7ff || + version == kVersionReserved || + layer == kLayerReserved || + bitrate_index == kBitrateFree || bitrate_index == kBitrateBad || + sample_rate_index == kSampleRateReserved) { + MEDIA_LOG(log_cb_) << "Invalid header data :" << std::hex + << " sync 0x" << sync + << " version 0x" << version + << " layer 0x" << layer + << " bitrate_index 0x" << bitrate_index + << " sample_rate_index 0x" << sample_rate_index + << " channel_mode 0x" << channel_mode; + return -1; + } + + if (layer == kLayer2 && kIsAllowed[bitrate_index][channel_mode]) { + MEDIA_LOG(log_cb_) << "Invalid (bitrate_index, channel_mode) combination :" + << std::hex + << " bitrate_index " << bitrate_index + << " channel_mode " << channel_mode; + return -1; + } + + int bitrate = kBitrateMap[bitrate_index][kVersionLayerMap[version][layer]]; + + if (bitrate == 0) { + MEDIA_LOG(log_cb_) << "Invalid bitrate :" << std::hex + << " version " << version + << " layer " << layer + << " bitrate_index " << bitrate_index; + return -1; + } + + DVLOG(2) << " bitrate " << bitrate; + + int frame_sample_rate = kSampleRateMap[sample_rate_index][version]; + if (frame_sample_rate == 0) { + MEDIA_LOG(log_cb_) << "Invalid sample rate :" << std::hex + << " version " << version + << " sample_rate_index " << sample_rate_index; + return -1; + } + + if (sample_rate) + *sample_rate = frame_sample_rate; + + // http://teslabs.com/openplayer/docs/docs/specs/mp3_structure2.pdf + // Table 2.1.5 + int samples_per_frame; + switch (layer) { + case kLayer1: + samples_per_frame = 384; + break; + + case kLayer2: + samples_per_frame = 1152; + break; + + case kLayer3: + if (version == kVersion2 || version == kVersion2_5) + samples_per_frame = 576; + else + samples_per_frame = 1152; + break; + + default: + return -1; + } + + if (sample_count) + *sample_count = samples_per_frame; + + // http://teslabs.com/openplayer/docs/docs/specs/mp3_structure2.pdf + // Text just below Table 2.1.5. + if (layer == kLayer1) { + // This formulation is a slight variation on the equation below, + // but has slightly different truncation characteristics to deal + // with the fact that Layer 1 has 4 byte "slots" instead of single + // byte ones. + *frame_size = 4 * (12 * bitrate * 1000 / frame_sample_rate); + } else { + *frame_size = + ((samples_per_frame / 8) * bitrate * 1000) / frame_sample_rate; + } + + if (has_padding) + *frame_size += (layer == kLayer1) ? 4 : 1; + + if (channel_layout) { + // Map Stereo(0), Joint Stereo(1), and Dual Channel (2) to + // CHANNEL_LAYOUT_STEREO and Single Channel (3) to CHANNEL_LAYOUT_MONO. + *channel_layout = + (channel_mode == 3) ? CHANNEL_LAYOUT_MONO : CHANNEL_LAYOUT_STEREO; + } + + return 4; +} + +int MP3StreamParser::ParseMP3Frame(const uint8* data, + int size, + BufferQueue* buffers) { + DVLOG(2) << __FUNCTION__ << "(" << size << ")"; + + int sample_rate; + ChannelLayout channel_layout; + int frame_size; + int sample_count; + int bytes_read = ParseFrameHeader( + data, size, &frame_size, &sample_rate, &channel_layout, &sample_count); + + if (bytes_read <= 0) + return bytes_read; + + // Make sure data contains the entire frame. + if (size < frame_size) + return 0; + + DVLOG(2) << " sample_rate " << sample_rate + << " channel_layout " << channel_layout + << " frame_size " << frame_size; + + if (config_.IsValidConfig() && + (config_.samples_per_second() != sample_rate || + config_.channel_layout() != channel_layout)) { + // Clear config data so that a config change is initiated. + config_ = AudioDecoderConfig(); + + // Send all buffers associated with the previous config. + if (!buffers->empty() && !SendBuffers(buffers, true)) + return -1; + } + + if (!config_.IsValidConfig()) { + config_.Initialize(kCodecMP3, kSampleFormatF32, channel_layout, + sample_rate, NULL, 0, false, false, + base::TimeDelta(), base::TimeDelta()); + + base::TimeDelta base_timestamp; + if (timestamp_helper_) + base_timestamp = timestamp_helper_->GetTimestamp(); + + timestamp_helper_.reset(new AudioTimestampHelper(sample_rate)); + timestamp_helper_->SetBaseTimestamp(base_timestamp); + + VideoDecoderConfig video_config; + bool success = config_cb_.Run(config_, video_config); + + if (!init_cb_.is_null()) + base::ResetAndReturn(&init_cb_).Run(success, kInfiniteDuration()); + + if (!success) + return -1; + } + + scoped_refptr<StreamParserBuffer> buffer = + StreamParserBuffer::CopyFrom(data, frame_size, true); + buffer->set_timestamp(timestamp_helper_->GetTimestamp()); + buffer->set_duration(timestamp_helper_->GetFrameDuration(sample_count)); + buffers->push_back(buffer); + + timestamp_helper_->AddFrames(sample_count); + + return frame_size; +} + +int MP3StreamParser::ParseIcecastHeader(const uint8* data, int size) { + DVLOG(1) << __FUNCTION__ << "(" << size << ")"; + + if (size < 4) + return 0; + + if (memcmp("ICY ", data, 4)) + return -1; + + int locate_size = std::min(size, kMaxIcecastHeaderSize); + int offset = net::HttpUtil::LocateEndOfHeaders( + reinterpret_cast<const char*>(data), locate_size, 4); + if (offset < 0) { + if (locate_size == kMaxIcecastHeaderSize) { + MEDIA_LOG(log_cb_) << "Icecast header is too large."; + return -1; + } + + return 0; + } + + return offset; +} + +int MP3StreamParser::ParseID3v1(const uint8* data, int size) { + DVLOG(1) << __FUNCTION__ << "(" << size << ")"; + + if (size < kID3v1Size) + return 0; + + // TODO(acolwell): Add code to actually validate ID3v1 data and + // expose it as a metadata text track. + return !memcmp(data, "TAG+", 4) ? kID3v1ExtendedSize : kID3v1Size; +} + +int MP3StreamParser::ParseID3v2(const uint8* data, int size) { + DVLOG(1) << __FUNCTION__ << "(" << size << ")"; + + if (size < 10) + return 0; + + BitReader reader(data, size); + int32 id; + int version; + uint8 flags; + int32 id3_size; + + if (!reader.ReadBits(24, &id) || + !reader.ReadBits(16, &version) || + !reader.ReadBits(8, &flags) || + !ParseSyncSafeInt(&reader, &id3_size)) { + return -1; + } + + int32 actual_tag_size = 10 + id3_size; + + // Increment size if 'Footer present' flag is set. + if (flags & 0x10) + actual_tag_size += 10; + + // Make sure we have the entire tag. + if (size < actual_tag_size) + return 0; + + // TODO(acolwell): Add code to actually validate ID3v2 data and + // expose it as a metadata text track. + return actual_tag_size; +} + +bool MP3StreamParser::ParseSyncSafeInt(BitReader* reader, int32* value) { + *value = 0; + for (int i = 0; i < 4; ++i) { + uint8 tmp; + if (!reader->ReadBits(1, &tmp) || tmp != 0) { + MEDIA_LOG(log_cb_) << "ID3 syncsafe integer byte MSb is not 0!"; + return false; + } + + if (!reader->ReadBits(7, &tmp)) + return false; + + *value <<= 7; + *value += tmp; + } + + return true; +} + +int MP3StreamParser::FindNextValidStartCode(const uint8* data, int size) const { + const uint8* start = data; + const uint8* end = data + size; + + while (start < end) { + int bytes_left = end - start; + const uint8* candidate_start_code = + static_cast<const uint8*>(memchr(start, 0xff, bytes_left)); + + if (!candidate_start_code) + return 0; + + bool parse_header_failed = false; + const uint8* sync = candidate_start_code; + // Try to find 3 valid frames in a row. 3 was selected to decrease + // the probability of false positives. + for (int i = 0; i < 3; ++i) { + int sync_size = end - sync; + int frame_size; + int sync_bytes = ParseFrameHeader( + sync, sync_size, &frame_size, NULL, NULL, NULL); + + if (sync_bytes == 0) + return 0; + + if (sync_bytes > 0) { + DCHECK_LT(sync_bytes, sync_size); + + // Skip over this frame so we can check the next one. + sync += frame_size; + + // Make sure the next frame starts inside the buffer. + if (sync >= end) + return 0; + } else { + DVLOG(1) << "ParseFrameHeader() " << i << " failed @" << (sync - data); + parse_header_failed = true; + break; + } + } + + if (parse_header_failed) { + // One of the frame header parses failed so |candidate_start_code| + // did not point to the start of a real frame. Move |start| forward + // so we can find the next candidate. + start = candidate_start_code + 1; + continue; + } + + return candidate_start_code - data; + } + + return 0; +} + +bool MP3StreamParser::SendBuffers(BufferQueue* buffers, bool end_of_segment) { + DCHECK(!buffers->empty()); + + if (!in_media_segment_) { + in_media_segment_ = true; + new_segment_cb_.Run(); + } + + BufferQueue empty_video_buffers; + if (!new_buffers_cb_.Run(*buffers, empty_video_buffers)) + return false; + buffers->clear(); + + if (end_of_segment) { + in_media_segment_ = false; + end_of_segment_cb_.Run(); + } + + return true; +} + +} // namespace media |