blob: 22df52244525ce36f0e1f2206a2e7c2195fc156a [file] [log] [blame]
/*
* 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/avc_utils.h"
#include "include/ID3.h"
#include "include/VBRISeeker.h"
#include "include/XINGSeeker.h"
#include <media/stagefright/foundation/ADebug.h>
#include <media/stagefright/foundation/AMessage.h>
#include <media/stagefright/DataSource.h>
#include <media/stagefright/MediaBuffer.h>
#include <media/stagefright/MediaBufferGroup.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, mode extension,
// copyright bit, original bit and emphasis.
// Yes ... there are things that must indeed match...
static const uint32_t kMask = 0xfffe0c00;
static bool Resync(
const sp<DataSource> &source, uint32_t match_header,
off64_t *inout_pos, off64_t *post_id3_pos, uint32_t *out_header) {
if (post_id3_pos != NULL) {
*post_id3_pos = 0;
}
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;
ALOGV("skipped ID3 tag, new starting offset is %lld (0x%016llx)",
(long long)*inout_pos, (long long)*inout_pos);
}
if (post_id3_pos != NULL) {
*post_id3_pos = *inout_pos;
}
}
off64_t pos = *inout_pos;
bool valid = false;
const size_t kMaxReadBytes = 1024;
const size_t kMaxBytesChecked = 128 * 1024;
uint8_t buf[kMaxReadBytes];
ssize_t bytesToRead = kMaxReadBytes;
ssize_t totalBytesRead = 0;
ssize_t remainingBytes = 0;
bool reachEOS = false;
uint8_t *tmp = buf;
do {
if (pos >= (off64_t)(*inout_pos + kMaxBytesChecked)) {
// Don't scan forever.
ALOGV("giving up at offset %lld", (long long)pos);
break;
}
if (remainingBytes < 4) {
if (reachEOS) {
break;
} else {
memcpy(buf, tmp, remainingBytes);
bytesToRead = kMaxReadBytes - remainingBytes;
/*
* The next read position should start from the end of
* the last buffer, and thus should include the remaining
* bytes in the buffer.
*/
totalBytesRead = source->readAt(pos + remainingBytes,
buf + remainingBytes,
bytesToRead);
if (totalBytesRead <= 0) {
break;
}
reachEOS = (totalBytesRead != bytesToRead);
totalBytesRead += remainingBytes;
remainingBytes = totalBytesRead;
tmp = buf;
continue;
}
}
uint32_t header = U32_AT(tmp);
if (match_header != 0 && (header & kMask) != (match_header & kMask)) {
++pos;
++tmp;
--remainingBytes;
continue;
}
size_t frame_size;
int sample_rate, num_channels, bitrate;
if (!GetMPEGAudioFrameSize(
header, &frame_size,
&sample_rate, &num_channels, &bitrate)) {
++pos;
++tmp;
--remainingBytes;
continue;
}
ALOGV("found possible 1st frame at %lld (header = 0x%08x)", (long long)pos, header);
// We found what looks like a valid frame,
// now find its successors.
off64_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);
ALOGV("subsequent header is %08x", test_header);
if ((test_header & kMask) != (header & kMask)) {
valid = false;
break;
}
size_t test_frame_size;
if (!GetMPEGAudioFrameSize(
test_header, &test_frame_size)) {
valid = false;
break;
}
ALOGV("found subsequent frame #%d at %lld", j + 2, (long long)test_pos);
test_pos += test_frame_size;
}
if (valid) {
*inout_pos = pos;
if (out_header != NULL) {
*out_header = header;
}
} else {
ALOGV("no dice, no valid sequence of frames found.");
}
++pos;
++tmp;
--remainingBytes;
} while (!valid);
return valid;
}
class MP3Source : public MediaSource {
public:
MP3Source(
const sp<MetaData> &meta, const sp<DataSource> &source,
off64_t first_frame_pos, uint32_t fixed_header,
const sp<MP3Seeker> &seeker);
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:
static const size_t kMaxFrameSize;
sp<MetaData> mMeta;
sp<DataSource> mDataSource;
off64_t mFirstFramePos;
uint32_t mFixedHeader;
off64_t mCurrentPos;
int64_t mCurrentTimeUs;
bool mStarted;
sp<MP3Seeker> mSeeker;
MediaBufferGroup *mGroup;
int64_t mBasisTimeUs;
int64_t mSamplesRead;
MP3Source(const MP3Source &);
MP3Source &operator=(const MP3Source &);
};
MP3Extractor::MP3Extractor(
const sp<DataSource> &source, const sp<AMessage> &meta)
: mInitCheck(NO_INIT),
mDataSource(source),
mFirstFramePos(-1),
mFixedHeader(0) {
off64_t pos = 0;
off64_t post_id3_pos;
uint32_t header;
bool success;
int64_t meta_offset;
uint32_t meta_header;
int64_t meta_post_id3_offset;
if (meta != NULL
&& meta->findInt64("offset", &meta_offset)
&& meta->findInt32("header", (int32_t *)&meta_header)
&& meta->findInt64("post-id3-offset", &meta_post_id3_offset)) {
// The sniffer has already done all the hard work for us, simply
// accept its judgement.
pos = (off64_t)meta_offset;
header = meta_header;
post_id3_pos = (off64_t)meta_post_id3_offset;
success = true;
} else {
success = Resync(mDataSource, 0, &pos, &post_id3_pos, &header);
}
if (!success) {
// mInitCheck will remain NO_INIT
return;
}
mFirstFramePos = pos;
mFixedHeader = header;
mMeta = new MetaData;
sp<XINGSeeker> seeker = XINGSeeker::CreateFromSource(mDataSource, mFirstFramePos);
if (seeker == NULL) {
mSeeker = VBRISeeker::CreateFromSource(mDataSource, post_id3_pos);
} else {
mSeeker = seeker;
int encd = seeker->getEncoderDelay();
int encp = seeker->getEncoderPadding();
if (encd != 0 || encp != 0) {
mMeta->setInt32(kKeyEncoderDelay, encd);
mMeta->setInt32(kKeyEncoderPadding, encp);
}
}
if (mSeeker != NULL) {
// While it is safe to send the XING/VBRI frame to the decoder, this will
// result in an extra 1152 samples being output. In addition, the bitrate
// of the Xing header might not match the rest of the file, which could
// lead to problems when seeking. The real first frame to decode is after
// the XING/VBRI frame, so skip there.
size_t frame_size;
int sample_rate;
int num_channels;
int bitrate;
GetMPEGAudioFrameSize(
header, &frame_size, &sample_rate, &num_channels, &bitrate);
pos += frame_size;
if (!Resync(mDataSource, 0, &pos, &post_id3_pos, &header)) {
// mInitCheck will remain NO_INIT
return;
}
mFirstFramePos = pos;
mFixedHeader = header;
}
size_t frame_size;
int sample_rate;
int num_channels;
int bitrate;
GetMPEGAudioFrameSize(
header, &frame_size, &sample_rate, &num_channels, &bitrate);
unsigned layer = 4 - ((header >> 17) & 3);
switch (layer) {
case 1:
mMeta->setCString(kKeyMIMEType, MEDIA_MIMETYPE_AUDIO_MPEG_LAYER_I);
break;
case 2:
mMeta->setCString(kKeyMIMEType, MEDIA_MIMETYPE_AUDIO_MPEG_LAYER_II);
break;
case 3:
mMeta->setCString(kKeyMIMEType, MEDIA_MIMETYPE_AUDIO_MPEG);
break;
default:
TRESPASS();
}
mMeta->setInt32(kKeySampleRate, sample_rate);
mMeta->setInt32(kKeyBitRate, bitrate * 1000);
mMeta->setInt32(kKeyChannelCount, num_channels);
int64_t durationUs;
if (mSeeker == NULL || !mSeeker->getDuration(&durationUs)) {
off64_t fileSize;
if (mDataSource->getSize(&fileSize) == OK) {
off64_t dataLength = fileSize - mFirstFramePos;
if (dataLength > INT64_MAX / 8000LL) {
// duration would overflow
durationUs = INT64_MAX;
} else {
durationUs = 8000LL * dataLength / bitrate;
}
} else {
durationUs = -1;
}
}
if (durationUs >= 0) {
mMeta->setInt64(kKeyDuration, durationUs);
}
mInitCheck = OK;
// Get iTunes-style gapless info if present.
// When getting the id3 tag, skip the V1 tags to prevent the source cache
// from being iterated to the end of the file.
ID3 id3(mDataSource, true);
if (id3.isValid()) {
ID3::Iterator *com = new ID3::Iterator(id3, "COM");
if (com->done()) {
delete com;
com = new ID3::Iterator(id3, "COMM");
}
while(!com->done()) {
String8 commentdesc;
String8 commentvalue;
com->getString(&commentdesc, &commentvalue);
const char * desc = commentdesc.string();
const char * value = commentvalue.string();
// first 3 characters are the language, which we don't care about
if(strlen(desc) > 3 && strcmp(desc + 3, "iTunSMPB") == 0) {
int32_t delay, padding;
if (sscanf(value, " %*x %x %x %*x", &delay, &padding) == 2) {
mMeta->setInt32(kKeyEncoderDelay, delay);
mMeta->setInt32(kKeyEncoderPadding, padding);
}
break;
}
com->next();
}
delete com;
com = NULL;
}
}
size_t MP3Extractor::countTracks() {
return mInitCheck != OK ? 0 : 1;
}
sp<IMediaSource> MP3Extractor::getTrack(size_t index) {
if (mInitCheck != OK || index != 0) {
return NULL;
}
return new MP3Source(
mMeta, mDataSource, mFirstFramePos, mFixedHeader,
mSeeker);
}
sp<MetaData> MP3Extractor::getTrackMetaData(
size_t index, uint32_t /* flags */) {
if (mInitCheck != OK || index != 0) {
return NULL;
}
return mMeta;
}
////////////////////////////////////////////////////////////////////////////////
// The theoretical maximum frame size for an MPEG audio stream should occur
// while playing a Layer 2, MPEGv2.5 audio stream at 160kbps (with padding).
// The size of this frame should be...
// ((1152 samples/frame * 160000 bits/sec) /
// (8000 samples/sec * 8 bits/byte)) + 1 padding byte/frame = 2881 bytes/frame.
// Set our max frame size to the nearest power of 2 above this size (aka, 4kB)
const size_t MP3Source::kMaxFrameSize = (1 << 12); /* 4096 bytes */
MP3Source::MP3Source(
const sp<MetaData> &meta, const sp<DataSource> &source,
off64_t first_frame_pos, uint32_t fixed_header,
const sp<MP3Seeker> &seeker)
: mMeta(meta),
mDataSource(source),
mFirstFramePos(first_frame_pos),
mFixedHeader(fixed_header),
mCurrentPos(0),
mCurrentTimeUs(0),
mStarted(false),
mSeeker(seeker),
mGroup(NULL),
mBasisTimeUs(0),
mSamplesRead(0) {
}
MP3Source::~MP3Source() {
if (mStarted) {
stop();
}
}
status_t MP3Source::start(MetaData *) {
CHECK(!mStarted);
mGroup = new MediaBufferGroup;
mGroup->add_buffer(new MediaBuffer(kMaxFrameSize));
mCurrentPos = mFirstFramePos;
mCurrentTimeUs = 0;
mBasisTimeUs = mCurrentTimeUs;
mSamplesRead = 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;
bool seekCBR = false;
if (options != NULL && options->getSeekTo(&seekTimeUs, &mode)) {
int64_t actualSeekTimeUs = seekTimeUs;
if (mSeeker == NULL
|| !mSeeker->getOffsetForTime(&actualSeekTimeUs, &mCurrentPos)) {
int32_t bitrate;
if (!mMeta->findInt32(kKeyBitRate, &bitrate)) {
// bitrate is in bits/sec.
ALOGI("no bitrate");
return ERROR_UNSUPPORTED;
}
mCurrentTimeUs = seekTimeUs;
mCurrentPos = mFirstFramePos + seekTimeUs * bitrate / 8000000;
seekCBR = true;
} else {
mCurrentTimeUs = actualSeekTimeUs;
}
mBasisTimeUs = mCurrentTimeUs;
mSamplesRead = 0;
}
MediaBuffer *buffer;
status_t err = mGroup->acquire_buffer(&buffer);
if (err != OK) {
return err;
}
size_t frame_size;
int bitrate;
int num_samples;
int sample_rate;
for (;;) {
ssize_t n = mDataSource->readAt(mCurrentPos, buffer->data(), 4);
if (n < 4) {
buffer->release();
buffer = NULL;
return (n < 0 ? n : ERROR_END_OF_STREAM);
}
uint32_t header = U32_AT((const uint8_t *)buffer->data());
if ((header & kMask) == (mFixedHeader & kMask)
&& GetMPEGAudioFrameSize(
header, &frame_size, &sample_rate, NULL,
&bitrate, &num_samples)) {
// re-calculate mCurrentTimeUs because we might have called Resync()
if (seekCBR) {
mCurrentTimeUs = (mCurrentPos - mFirstFramePos) * 8000 / bitrate;
mBasisTimeUs = mCurrentTimeUs;
}
break;
}
// Lost sync.
ALOGV("lost sync! header = 0x%08x, old header = 0x%08x\n", header, mFixedHeader);
off64_t pos = mCurrentPos;
if (!Resync(mDataSource, mFixedHeader, &pos, NULL, NULL)) {
ALOGE("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 (n < 0 ? n : 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;
mSamplesRead += num_samples;
mCurrentTimeUs = mBasisTimeUs + ((mSamplesRead * 1000000) / sample_rate);
*out = buffer;
return OK;
}
sp<MetaData> MP3Extractor::getMetaData() {
sp<MetaData> meta = new MetaData;
if (mInitCheck != OK) {
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" },
{ kKeyCompilation, "TCP", "TCMP" },
};
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, sp<AMessage> *meta) {
off64_t pos = 0;
off64_t post_id3_pos;
uint32_t header;
if (!Resync(source, 0, &pos, &post_id3_pos, &header)) {
return false;
}
*meta = new AMessage;
(*meta)->setInt64("offset", pos);
(*meta)->setInt32("header", header);
(*meta)->setInt64("post-id3-offset", post_id3_pos);
*mimeType = MEDIA_MIMETYPE_AUDIO_MPEG;
*confidence = 0.2f;
return true;
}
} // namespace android