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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_TAG "XINGSEEKER"
#include <utils/Log.h>
#include "include/XINGSeeker.h"
#include "include/avc_utils.h"
#include <media/stagefright/DataSource.h>
#include <media/stagefright/Utils.h>
namespace android {
XINGSeeker::XINGSeeker()
: mDurationUs(-1),
mSizeBytes(0),
mEncoderDelay(0),
mEncoderPadding(0),
mTOCValid(false) {
}
bool XINGSeeker::getDuration(int64_t *durationUs) {
if (mDurationUs < 0) {
return false;
}
*durationUs = mDurationUs;
return true;
}
bool XINGSeeker::getOffsetForTime(int64_t *timeUs, off64_t *pos) {
if (mSizeBytes == 0 || !mTOCValid || mDurationUs < 0) {
return false;
}
float percent = (float)(*timeUs) * 100 / mDurationUs;
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)mTOC[a-1];
}
if ( a < 99 ) {
fb = (float)mTOC[a];
} else {
fb = 256.0f;
}
fx = fa + (fb-fa)*(percent-a);
}
*pos = (int)((1.0f/256.0f)*fx*mSizeBytes) + mFirstFramePos;
return true;
}
// static
sp<XINGSeeker> XINGSeeker::CreateFromSource(
const sp<DataSource> &source, off64_t first_frame_pos) {
sp<XINGSeeker> seeker = new XINGSeeker;
seeker->mFirstFramePos = first_frame_pos;
uint8_t buffer[4];
int offset = first_frame_pos;
if (source->readAt(offset, &buffer, 4) < 4) { // get header
return NULL;
}
offset += 4;
int header = U32_AT(buffer);;
size_t xingframesize = 0;
int sampling_rate = 0;
int num_channels;
int samples_per_frame = 0;
if (!GetMPEGAudioFrameSize(header, &xingframesize, &sampling_rate, &num_channels,
NULL, &samples_per_frame)) {
return NULL;
}
seeker->mFirstFramePos += xingframesize;
uint8_t version = (buffer[1] >> 3) & 3;
// determine offset of XING header
if(version & 1) { // mpeg1
if (num_channels != 1) offset += 32;
else offset += 17;
} else { // mpeg 2 or 2.5
if (num_channels != 1) offset += 17;
else offset += 9;
}
int xingbase = offset;
if (source->readAt(offset, &buffer, 4) < 4) { // XING header ID
return NULL;
}
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 NULL;
}
}
if (source->readAt(offset, &buffer, 4) < 4) { // flags
return NULL;
}
offset += 4;
uint32_t flags = U32_AT(buffer);
if (flags & 0x0001) { // Frames field is present
if (source->readAt(offset, buffer, 4) < 4) {
return NULL;
}
int32_t frames = U32_AT(buffer);
// 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 xing tag does not have the
// requested information
if (frames) {
seeker->mDurationUs = (int64_t)frames * samples_per_frame * 1000000LL / sampling_rate;
}
offset += 4;
}
if (flags & 0x0002) { // Bytes field is present
if (source->readAt(offset, buffer, 4) < 4) {
return NULL;
}
seeker->mSizeBytes = U32_AT(buffer);
offset += 4;
}
if (flags & 0x0004) { // TOC field is present
if (source->readAt(offset + 1, seeker->mTOC, 99) < 99) {
return NULL;
}
seeker->mTOCValid = true;
offset += 100;
}
#if 0
if (flags & 0x0008) { // Quality indicator field is present
if (source->readAt(offset, buffer, 4) < 4) {
return NULL;
}
// do something with the quality indicator
offset += 4;
}
if (source->readAt(xingbase + 0xaf - 0x24, &buffer, 1) < 1) { // encoding flags
return false;
}
ALOGV("nogap preceding: %s, nogap continued in next: %s",
(buffer[0] & 0x80) ? "true" : "false",
(buffer[0] & 0x40) ? "true" : "false");
#endif
if (source->readAt(xingbase + 0xb1 - 0x24, &buffer, 3) == 3) {
seeker->mEncoderDelay = (buffer[0] << 4) + (buffer[1] >> 4);
seeker->mEncoderPadding = ((buffer[1] & 0xf) << 8) + buffer[2];
}
return seeker;
}
int32_t XINGSeeker::getEncoderDelay() {
return mEncoderDelay;
}
int32_t XINGSeeker::getEncoderPadding() {
return mEncoderPadding;
}
} // namespace android
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