| /* |
| * Copyright (C) 2009 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| //#define LOG_NDEBUG 0 |
| #define LOG_TAG "MP3Extractor" |
| #include <utils/Log.h> |
| |
| #include "include/MP3Extractor.h" |
| |
| #include "include/ID3.h" |
| |
| #include <media/stagefright/DataSource.h> |
| #include <media/stagefright/MediaBuffer.h> |
| #include <media/stagefright/MediaBufferGroup.h> |
| #include <media/stagefright/MediaDebug.h> |
| #include <media/stagefright/MediaDefs.h> |
| #include <media/stagefright/MediaErrors.h> |
| #include <media/stagefright/MediaSource.h> |
| #include <media/stagefright/MetaData.h> |
| #include <media/stagefright/Utils.h> |
| #include <utils/String8.h> |
| |
| namespace android { |
| |
| // Everything must match except for |
| // protection, bitrate, padding, private bits, mode extension, |
| // copyright bit, original bit and emphasis. |
| // Yes ... there are things that must indeed match... |
| static const uint32_t kMask = 0xfffe0cc0; |
| |
| static bool get_mp3_frame_size( |
| uint32_t header, size_t *frame_size, |
| int *out_sampling_rate = NULL, int *out_channels = NULL, |
| int *out_bitrate = NULL) { |
| *frame_size = 0; |
| |
| if (out_sampling_rate) { |
| *out_sampling_rate = 0; |
| } |
| |
| if (out_channels) { |
| *out_channels = 0; |
| } |
| |
| if (out_bitrate) { |
| *out_bitrate = 0; |
| } |
| |
| if ((header & 0xffe00000) != 0xffe00000) { |
| return false; |
| } |
| |
| unsigned version = (header >> 19) & 3; |
| |
| if (version == 0x01) { |
| return false; |
| } |
| |
| unsigned layer = (header >> 17) & 3; |
| |
| if (layer == 0x00) { |
| return false; |
| } |
| |
| unsigned protection = (header >> 16) & 1; |
| |
| unsigned bitrate_index = (header >> 12) & 0x0f; |
| |
| if (bitrate_index == 0 || bitrate_index == 0x0f) { |
| // Disallow "free" bitrate. |
| return false; |
| } |
| |
| unsigned sampling_rate_index = (header >> 10) & 3; |
| |
| if (sampling_rate_index == 3) { |
| return false; |
| } |
| |
| static const int kSamplingRateV1[] = { 44100, 48000, 32000 }; |
| int sampling_rate = kSamplingRateV1[sampling_rate_index]; |
| if (version == 2 /* V2 */) { |
| sampling_rate /= 2; |
| } else if (version == 0 /* V2.5 */) { |
| sampling_rate /= 4; |
| } |
| |
| unsigned padding = (header >> 9) & 1; |
| |
| if (layer == 3) { |
| // layer I |
| |
| static const int kBitrateV1[] = { |
| 32, 64, 96, 128, 160, 192, 224, 256, |
| 288, 320, 352, 384, 416, 448 |
| }; |
| |
| static const int kBitrateV2[] = { |
| 32, 48, 56, 64, 80, 96, 112, 128, |
| 144, 160, 176, 192, 224, 256 |
| }; |
| |
| int bitrate = |
| (version == 3 /* V1 */) |
| ? kBitrateV1[bitrate_index - 1] |
| : kBitrateV2[bitrate_index - 1]; |
| |
| if (out_bitrate) { |
| *out_bitrate = bitrate; |
| } |
| |
| *frame_size = (12000 * bitrate / sampling_rate + padding) * 4; |
| } else { |
| // layer II or III |
| |
| static const int kBitrateV1L2[] = { |
| 32, 48, 56, 64, 80, 96, 112, 128, |
| 160, 192, 224, 256, 320, 384 |
| }; |
| |
| static const int kBitrateV1L3[] = { |
| 32, 40, 48, 56, 64, 80, 96, 112, |
| 128, 160, 192, 224, 256, 320 |
| }; |
| |
| static const int kBitrateV2[] = { |
| 8, 16, 24, 32, 40, 48, 56, 64, |
| 80, 96, 112, 128, 144, 160 |
| }; |
| |
| int bitrate; |
| if (version == 3 /* V1 */) { |
| bitrate = (layer == 2 /* L2 */) |
| ? kBitrateV1L2[bitrate_index - 1] |
| : kBitrateV1L3[bitrate_index - 1]; |
| } else { |
| // V2 (or 2.5) |
| |
| bitrate = kBitrateV2[bitrate_index - 1]; |
| } |
| |
| if (out_bitrate) { |
| *out_bitrate = bitrate; |
| } |
| |
| if (version == 3 /* V1 */) { |
| *frame_size = 144000 * bitrate / sampling_rate + padding; |
| } else { |
| // V2 or V2.5 |
| *frame_size = 72000 * bitrate / sampling_rate + padding; |
| } |
| } |
| |
| if (out_sampling_rate) { |
| *out_sampling_rate = sampling_rate; |
| } |
| |
| if (out_channels) { |
| int channel_mode = (header >> 6) & 3; |
| |
| *out_channels = (channel_mode == 3) ? 1 : 2; |
| } |
| |
| return true; |
| } |
| |
| static bool parse_xing_header( |
| const sp<DataSource> &source, off_t first_frame_pos, |
| int32_t *frame_number = NULL, int32_t *byte_number = NULL, |
| char *table_of_contents = NULL, int32_t *quality_indicator = NULL, |
| int64_t *duration = NULL) { |
| |
| if (frame_number) { |
| *frame_number = 0; |
| } |
| if (byte_number) { |
| *byte_number = 0; |
| } |
| if (table_of_contents) { |
| table_of_contents[0] = 0; |
| } |
| if (quality_indicator) { |
| *quality_indicator = 0; |
| } |
| if (duration) { |
| *duration = 0; |
| } |
| |
| uint8_t buffer[4]; |
| int offset = first_frame_pos; |
| if (source->readAt(offset, &buffer, 4) < 4) { // get header |
| return false; |
| } |
| offset += 4; |
| |
| uint8_t id, layer, sr_index, mode; |
| layer = (buffer[1] >> 1) & 3; |
| id = (buffer[1] >> 3) & 3; |
| sr_index = (buffer[2] >> 2) & 3; |
| mode = (buffer[3] >> 6) & 3; |
| if (layer == 0) { |
| return false; |
| } |
| if (id == 1) { |
| return false; |
| } |
| if (sr_index == 3) { |
| return false; |
| } |
| // determine offset of XING header |
| if(id&1) { // mpeg1 |
| if (mode != 3) offset += 32; |
| else offset += 17; |
| } else { // mpeg2 |
| if (mode != 3) offset += 17; |
| else offset += 9; |
| } |
| |
| if (source->readAt(offset, &buffer, 4) < 4) { // XING header ID |
| return false; |
| } |
| offset += 4; |
| // Check XING ID |
| if ((buffer[0] != 'X') || (buffer[1] != 'i') |
| || (buffer[2] != 'n') || (buffer[3] != 'g')) { |
| if ((buffer[0] != 'I') || (buffer[1] != 'n') |
| || (buffer[2] != 'f') || (buffer[3] != 'o')) { |
| return false; |
| } |
| } |
| |
| if (source->readAt(offset, &buffer, 4) < 4) { // flags |
| return false; |
| } |
| offset += 4; |
| uint32_t flags = U32_AT(buffer); |
| |
| if (flags & 0x0001) { // Frames field is present |
| if (source->readAt(offset, buffer, 4) < 4) { |
| return false; |
| } |
| if (frame_number) { |
| *frame_number = U32_AT(buffer); |
| } |
| int32_t frame = U32_AT(buffer); |
| // Samples per Frame: 1. index = MPEG Version ID, 2. index = Layer |
| const int samplesPerFrames[2][3] = |
| { |
| { 384, 1152, 576 }, // MPEG 2, 2.5: layer1, layer2, layer3 |
| { 384, 1152, 1152 }, // MPEG 1: layer1, layer2, layer3 |
| }; |
| // sampling rates in hertz: 1. index = MPEG Version ID, 2. index = sampling rate index |
| const int samplingRates[4][3] = |
| { |
| { 11025, 12000, 8000, }, // MPEG 2.5 |
| { 0, 0, 0, }, // reserved |
| { 22050, 24000, 16000, }, // MPEG 2 |
| { 44100, 48000, 32000, } // MPEG 1 |
| }; |
| if (duration) { |
| *duration = (int64_t)frame * samplesPerFrames[id&1][3-layer] * 1000000LL |
| / samplingRates[id][sr_index]; |
| } |
| offset += 4; |
| } |
| if (flags & 0x0002) { // Bytes field is present |
| if (byte_number) { |
| if (source->readAt(offset, buffer, 4) < 4) { |
| return false; |
| } |
| *byte_number = U32_AT(buffer); |
| } |
| offset += 4; |
| } |
| if (flags & 0x0004) { // TOC field is present |
| if (table_of_contents) { |
| if (source->readAt(offset + 1, table_of_contents, 99) < 99) { |
| return false; |
| } |
| } |
| offset += 100; |
| } |
| if (flags & 0x0008) { // Quality indicator field is present |
| if (quality_indicator) { |
| if (source->readAt(offset, buffer, 4) < 4) { |
| return false; |
| } |
| *quality_indicator = U32_AT(buffer); |
| } |
| } |
| return true; |
| } |
| |
| static bool Resync( |
| const sp<DataSource> &source, uint32_t match_header, |
| off_t *inout_pos, uint32_t *out_header) { |
| if (*inout_pos == 0) { |
| // Skip an optional ID3 header if syncing at the very beginning |
| // of the datasource. |
| |
| for (;;) { |
| uint8_t id3header[10]; |
| if (source->readAt(*inout_pos, id3header, sizeof(id3header)) |
| < (ssize_t)sizeof(id3header)) { |
| // If we can't even read these 10 bytes, we might as well bail |
| // out, even if there _were_ 10 bytes of valid mp3 audio data... |
| return false; |
| } |
| |
| if (memcmp("ID3", id3header, 3)) { |
| break; |
| } |
| |
| // Skip the ID3v2 header. |
| |
| size_t len = |
| ((id3header[6] & 0x7f) << 21) |
| | ((id3header[7] & 0x7f) << 14) |
| | ((id3header[8] & 0x7f) << 7) |
| | (id3header[9] & 0x7f); |
| |
| len += 10; |
| |
| *inout_pos += len; |
| |
| LOGV("skipped ID3 tag, new starting offset is %ld (0x%08lx)", |
| *inout_pos, *inout_pos); |
| } |
| } |
| |
| off_t pos = *inout_pos; |
| bool valid = false; |
| do { |
| if (pos >= *inout_pos + 128 * 1024) { |
| // Don't scan forever. |
| LOGV("giving up at offset %ld", pos); |
| break; |
| } |
| |
| uint8_t tmp[4]; |
| if (source->readAt(pos, tmp, 4) != 4) { |
| break; |
| } |
| |
| uint32_t header = U32_AT(tmp); |
| |
| if (match_header != 0 && (header & kMask) != (match_header & kMask)) { |
| ++pos; |
| continue; |
| } |
| |
| size_t frame_size; |
| int sample_rate, num_channels, bitrate; |
| if (!get_mp3_frame_size(header, &frame_size, |
| &sample_rate, &num_channels, &bitrate)) { |
| ++pos; |
| continue; |
| } |
| |
| LOGV("found possible 1st frame at %ld (header = 0x%08x)", pos, header); |
| |
| // We found what looks like a valid frame, |
| // now find its successors. |
| |
| off_t test_pos = pos + frame_size; |
| |
| valid = true; |
| for (int j = 0; j < 3; ++j) { |
| uint8_t tmp[4]; |
| if (source->readAt(test_pos, tmp, 4) < 4) { |
| valid = false; |
| break; |
| } |
| |
| uint32_t test_header = U32_AT(tmp); |
| |
| LOGV("subsequent header is %08x", test_header); |
| |
| if ((test_header & kMask) != (header & kMask)) { |
| valid = false; |
| break; |
| } |
| |
| size_t test_frame_size; |
| if (!get_mp3_frame_size(test_header, &test_frame_size)) { |
| valid = false; |
| break; |
| } |
| |
| LOGV("found subsequent frame #%d at %ld", j + 2, test_pos); |
| |
| test_pos += test_frame_size; |
| } |
| |
| if (valid) { |
| *inout_pos = pos; |
| |
| if (out_header != NULL) { |
| *out_header = header; |
| } |
| } else { |
| LOGV("no dice, no valid sequence of frames found."); |
| } |
| |
| ++pos; |
| } while (!valid); |
| |
| return valid; |
| } |
| |
| class MP3Source : public MediaSource { |
| public: |
| MP3Source( |
| const sp<MetaData> &meta, const sp<DataSource> &source, |
| off_t first_frame_pos, uint32_t fixed_header, |
| int32_t byte_number, const char *table_of_contents); |
| |
| virtual status_t start(MetaData *params = NULL); |
| virtual status_t stop(); |
| |
| virtual sp<MetaData> getFormat(); |
| |
| virtual status_t read( |
| MediaBuffer **buffer, const ReadOptions *options = NULL); |
| |
| protected: |
| virtual ~MP3Source(); |
| |
| private: |
| sp<MetaData> mMeta; |
| sp<DataSource> mDataSource; |
| off_t mFirstFramePos; |
| uint32_t mFixedHeader; |
| off_t mCurrentPos; |
| int64_t mCurrentTimeUs; |
| bool mStarted; |
| int32_t mByteNumber; // total number of bytes in this MP3 |
| // TOC entries in XING header. Skip the first one since it's always 0. |
| char mTableOfContents[99]; |
| MediaBufferGroup *mGroup; |
| |
| MP3Source(const MP3Source &); |
| MP3Source &operator=(const MP3Source &); |
| }; |
| |
| MP3Extractor::MP3Extractor(const sp<DataSource> &source) |
| : mDataSource(source), |
| mFirstFramePos(-1), |
| mFixedHeader(0), |
| mByteNumber(0) { |
| off_t pos = 0; |
| uint32_t header; |
| bool success = Resync(mDataSource, 0, &pos, &header); |
| CHECK(success); |
| |
| if (success) { |
| mFirstFramePos = pos; |
| mFixedHeader = header; |
| |
| size_t frame_size; |
| int sample_rate; |
| int num_channels; |
| int bitrate; |
| get_mp3_frame_size( |
| header, &frame_size, &sample_rate, &num_channels, &bitrate); |
| |
| mMeta = new MetaData; |
| |
| mMeta->setCString(kKeyMIMEType, MEDIA_MIMETYPE_AUDIO_MPEG); |
| mMeta->setInt32(kKeySampleRate, sample_rate); |
| mMeta->setInt32(kKeyBitRate, bitrate * 1000); |
| mMeta->setInt32(kKeyChannelCount, num_channels); |
| |
| int64_t duration; |
| parse_xing_header( |
| mDataSource, mFirstFramePos, NULL, &mByteNumber, |
| mTableOfContents, NULL, &duration); |
| if (duration > 0) { |
| mMeta->setInt64(kKeyDuration, duration); |
| } else { |
| off_t fileSize; |
| if (mDataSource->getSize(&fileSize) == OK) { |
| mMeta->setInt64( |
| kKeyDuration, |
| 8000LL * (fileSize - mFirstFramePos) / bitrate); |
| } |
| } |
| } |
| } |
| |
| MP3Extractor::~MP3Extractor() { |
| } |
| |
| size_t MP3Extractor::countTracks() { |
| return (mFirstFramePos < 0) ? 0 : 1; |
| } |
| |
| sp<MediaSource> MP3Extractor::getTrack(size_t index) { |
| if (mFirstFramePos < 0 || index != 0) { |
| return NULL; |
| } |
| |
| return new MP3Source( |
| mMeta, mDataSource, mFirstFramePos, mFixedHeader, |
| mByteNumber, mTableOfContents); |
| } |
| |
| sp<MetaData> MP3Extractor::getTrackMetaData(size_t index, uint32_t flags) { |
| if (mFirstFramePos < 0 || index != 0) { |
| return NULL; |
| } |
| |
| return mMeta; |
| } |
| |
| //////////////////////////////////////////////////////////////////////////////// |
| |
| MP3Source::MP3Source( |
| const sp<MetaData> &meta, const sp<DataSource> &source, |
| off_t first_frame_pos, uint32_t fixed_header, |
| int32_t byte_number, const char *table_of_contents) |
| : mMeta(meta), |
| mDataSource(source), |
| mFirstFramePos(first_frame_pos), |
| mFixedHeader(fixed_header), |
| mCurrentPos(0), |
| mCurrentTimeUs(0), |
| mStarted(false), |
| mByteNumber(byte_number), |
| mGroup(NULL) { |
| memcpy (mTableOfContents, table_of_contents, sizeof(mTableOfContents)); |
| } |
| |
| MP3Source::~MP3Source() { |
| if (mStarted) { |
| stop(); |
| } |
| } |
| |
| status_t MP3Source::start(MetaData *) { |
| CHECK(!mStarted); |
| |
| mGroup = new MediaBufferGroup; |
| |
| const size_t kMaxFrameSize = 32768; |
| mGroup->add_buffer(new MediaBuffer(kMaxFrameSize)); |
| |
| mCurrentPos = mFirstFramePos; |
| mCurrentTimeUs = 0; |
| |
| mStarted = true; |
| |
| return OK; |
| } |
| |
| status_t MP3Source::stop() { |
| CHECK(mStarted); |
| |
| delete mGroup; |
| mGroup = NULL; |
| |
| mStarted = false; |
| |
| return OK; |
| } |
| |
| sp<MetaData> MP3Source::getFormat() { |
| return mMeta; |
| } |
| |
| status_t MP3Source::read( |
| MediaBuffer **out, const ReadOptions *options) { |
| *out = NULL; |
| |
| int64_t seekTimeUs; |
| ReadOptions::SeekMode mode; |
| if (options != NULL && options->getSeekTo(&seekTimeUs, &mode)) { |
| int32_t bitrate; |
| if (!mMeta->findInt32(kKeyBitRate, &bitrate)) { |
| // bitrate is in bits/sec. |
| LOGI("no bitrate"); |
| |
| return ERROR_UNSUPPORTED; |
| } |
| |
| mCurrentTimeUs = seekTimeUs; |
| // interpolate in TOC to get file seek point in bytes |
| int64_t duration; |
| if ((mByteNumber > 0) && (mTableOfContents[0] > 0) |
| && mMeta->findInt64(kKeyDuration, &duration)) { |
| float percent = (float)seekTimeUs * 100 / duration; |
| float fx; |
| if( percent <= 0.0f ) { |
| fx = 0.0f; |
| } else if( percent >= 100.0f ) { |
| fx = 256.0f; |
| } else { |
| int a = (int)percent; |
| float fa, fb; |
| if ( a == 0 ) { |
| fa = 0.0f; |
| } else { |
| fa = (float)mTableOfContents[a-1]; |
| } |
| if ( a < 99 ) { |
| fb = (float)mTableOfContents[a]; |
| } else { |
| fb = 256.0f; |
| } |
| fx = fa + (fb-fa)*(percent-a); |
| } |
| mCurrentPos = mFirstFramePos + (int)((1.0f/256.0f)*fx*mByteNumber); |
| } else { |
| mCurrentPos = mFirstFramePos + seekTimeUs * bitrate / 8000000; |
| } |
| } |
| |
| MediaBuffer *buffer; |
| status_t err = mGroup->acquire_buffer(&buffer); |
| if (err != OK) { |
| return err; |
| } |
| |
| size_t frame_size; |
| int bitrate; |
| for (;;) { |
| ssize_t n = mDataSource->readAt(mCurrentPos, buffer->data(), 4); |
| if (n < 4) { |
| buffer->release(); |
| buffer = NULL; |
| |
| return ERROR_END_OF_STREAM; |
| } |
| |
| uint32_t header = U32_AT((const uint8_t *)buffer->data()); |
| |
| if ((header & kMask) == (mFixedHeader & kMask) |
| && get_mp3_frame_size(header, &frame_size, NULL, NULL, &bitrate)) { |
| break; |
| } |
| |
| // Lost sync. |
| LOGV("lost sync! header = 0x%08x, old header = 0x%08x\n", header, mFixedHeader); |
| |
| off_t pos = mCurrentPos; |
| if (!Resync(mDataSource, mFixedHeader, &pos, NULL)) { |
| LOGE("Unable to resync. Signalling end of stream."); |
| |
| buffer->release(); |
| buffer = NULL; |
| |
| return ERROR_END_OF_STREAM; |
| } |
| |
| mCurrentPos = pos; |
| |
| // Try again with the new position. |
| } |
| |
| CHECK(frame_size <= buffer->size()); |
| |
| ssize_t n = mDataSource->readAt(mCurrentPos, buffer->data(), frame_size); |
| if (n < (ssize_t)frame_size) { |
| buffer->release(); |
| buffer = NULL; |
| |
| return ERROR_END_OF_STREAM; |
| } |
| |
| buffer->set_range(0, frame_size); |
| |
| buffer->meta_data()->setInt64(kKeyTime, mCurrentTimeUs); |
| buffer->meta_data()->setInt32(kKeyIsSyncFrame, 1); |
| |
| mCurrentPos += frame_size; |
| mCurrentTimeUs += frame_size * 8000ll / bitrate; |
| |
| *out = buffer; |
| |
| return OK; |
| } |
| |
| sp<MetaData> MP3Extractor::getMetaData() { |
| sp<MetaData> meta = new MetaData; |
| |
| if (mFirstFramePos < 0) { |
| return meta; |
| } |
| |
| meta->setCString(kKeyMIMEType, "audio/mpeg"); |
| |
| ID3 id3(mDataSource); |
| |
| if (!id3.isValid()) { |
| return meta; |
| } |
| |
| struct Map { |
| int key; |
| const char *tag1; |
| const char *tag2; |
| }; |
| static const Map kMap[] = { |
| { kKeyAlbum, "TALB", "TAL" }, |
| { kKeyArtist, "TPE1", "TP1" }, |
| { kKeyAlbumArtist, "TPE2", "TP2" }, |
| { kKeyComposer, "TCOM", "TCM" }, |
| { kKeyGenre, "TCON", "TCO" }, |
| { kKeyTitle, "TIT2", "TT2" }, |
| { kKeyYear, "TYE", "TYER" }, |
| { kKeyAuthor, "TXT", "TEXT" }, |
| { kKeyCDTrackNumber, "TRK", "TRCK" }, |
| { kKeyDiscNumber, "TPA", "TPOS" }, |
| }; |
| static const size_t kNumMapEntries = sizeof(kMap) / sizeof(kMap[0]); |
| |
| for (size_t i = 0; i < kNumMapEntries; ++i) { |
| ID3::Iterator *it = new ID3::Iterator(id3, kMap[i].tag1); |
| if (it->done()) { |
| delete it; |
| it = new ID3::Iterator(id3, kMap[i].tag2); |
| } |
| |
| if (it->done()) { |
| delete it; |
| continue; |
| } |
| |
| String8 s; |
| it->getString(&s); |
| delete it; |
| |
| meta->setCString(kMap[i].key, s); |
| } |
| |
| size_t dataSize; |
| String8 mime; |
| const void *data = id3.getAlbumArt(&dataSize, &mime); |
| |
| if (data) { |
| meta->setData(kKeyAlbumArt, MetaData::TYPE_NONE, data, dataSize); |
| meta->setCString(kKeyAlbumArtMIME, mime.string()); |
| } |
| |
| return meta; |
| } |
| |
| bool SniffMP3( |
| const sp<DataSource> &source, String8 *mimeType, float *confidence) { |
| off_t pos = 0; |
| uint32_t header; |
| if (!Resync(source, 0, &pos, &header)) { |
| return false; |
| } |
| |
| *mimeType = MEDIA_MIMETYPE_AUDIO_MPEG; |
| *confidence = 0.3f; |
| |
| return true; |
| } |
| |
| } // namespace android |
