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/*
* Copyright (C) 2010 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 "VBRISeeker"
#include <inttypes.h>
#include <utils/Log.h>
#include "include/VBRISeeker.h"
#include "include/avc_utils.h"
#include "include/MP3Extractor.h"
#include <media/stagefright/foundation/ADebug.h>
#include <media/stagefright/DataSource.h>
#include <media/stagefright/Utils.h>
namespace android {
static uint32_t U24_AT(const uint8_t *ptr) {
return ptr[0] << 16 | ptr[1] << 8 | ptr[2];
}
// static
sp<VBRISeeker> VBRISeeker::CreateFromSource(
const sp<DataSource> &source, off64_t post_id3_pos) {
off64_t pos = post_id3_pos;
uint8_t header[4];
ssize_t n = source->readAt(pos, header, sizeof(header));
if (n < (ssize_t)sizeof(header)) {
return NULL;
}
uint32_t tmp = U32_AT(&header[0]);
size_t frameSize;
int sampleRate;
if (!GetMPEGAudioFrameSize(tmp, &frameSize, &sampleRate)) {
return NULL;
}
// VBRI header follows 32 bytes after the header _ends_.
pos += sizeof(header) + 32;
uint8_t vbriHeader[26];
n = source->readAt(pos, vbriHeader, sizeof(vbriHeader));
if (n < (ssize_t)sizeof(vbriHeader)) {
return NULL;
}
if (memcmp(vbriHeader, "VBRI", 4)) {
return NULL;
}
size_t numFrames = U32_AT(&vbriHeader[14]);
int64_t durationUs =
numFrames * 1000000ll * (sampleRate >= 32000 ? 1152 : 576) / sampleRate;
ALOGV("duration = %.2f secs", durationUs / 1E6);
size_t numEntries = U16_AT(&vbriHeader[18]);
size_t entrySize = U16_AT(&vbriHeader[22]);
size_t scale = U16_AT(&vbriHeader[20]);
ALOGV("%zu entries, scale=%zu, size_per_entry=%zu",
numEntries,
scale,
entrySize);
if (entrySize > 4) {
ALOGE("invalid VBRI entry size: %zu", entrySize);
return NULL;
}
sp<VBRISeeker> seeker = new (std::nothrow) VBRISeeker;
if (seeker == NULL) {
ALOGW("Couldn't allocate VBRISeeker");
return NULL;
}
size_t totalEntrySize = numEntries * entrySize;
uint8_t *buffer = new (std::nothrow) uint8_t[totalEntrySize];
if (!buffer) {
ALOGW("Couldn't allocate %zu bytes", totalEntrySize);
return NULL;
}
n = source->readAt(pos + sizeof(vbriHeader), buffer, totalEntrySize);
if (n < (ssize_t)totalEntrySize) {
delete[] buffer;
buffer = NULL;
return NULL;
}
seeker->mBasePos = post_id3_pos + frameSize;
// only update mDurationUs if the calculated duration is valid (non zero)
// otherwise, leave duration at -1 so that getDuration() and getOffsetForTime()
// return false when called, to indicate that this vbri tag does not have the
// requested information
if (durationUs) {
seeker->mDurationUs = durationUs;
}
off64_t offset = post_id3_pos;
for (size_t i = 0; i < numEntries; ++i) {
uint32_t numBytes;
switch (entrySize) {
case 1: numBytes = buffer[i]; break;
case 2: numBytes = U16_AT(buffer + 2 * i); break;
case 3: numBytes = U24_AT(buffer + 3 * i); break;
default:
{
CHECK_EQ(entrySize, 4u);
numBytes = U32_AT(buffer + 4 * i); break;
}
}
numBytes *= scale;
seeker->mSegments.push(numBytes);
ALOGV("entry #%zu: %u offset %#016llx", i, numBytes, (long long)offset);
offset += numBytes;
}
delete[] buffer;
buffer = NULL;
ALOGI("Found VBRI header.");
return seeker;
}
VBRISeeker::VBRISeeker()
: mDurationUs(-1) {
}
bool VBRISeeker::getDuration(int64_t *durationUs) {
if (mDurationUs < 0) {
return false;
}
*durationUs = mDurationUs;
return true;
}
bool VBRISeeker::getOffsetForTime(int64_t *timeUs, off64_t *pos) {
if (mDurationUs < 0) {
return false;
}
int64_t segmentDurationUs = mDurationUs / mSegments.size();
int64_t nowUs = 0;
*pos = mBasePos;
size_t segmentIndex = 0;
while (segmentIndex < mSegments.size() && nowUs < *timeUs) {
nowUs += segmentDurationUs;
*pos += mSegments.itemAt(segmentIndex++);
}
ALOGV("getOffsetForTime %lld us => 0x%016llx", (long long)*timeUs, (long long)*pos);
*timeUs = nowUs;
return true;
}
} // namespace android
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