Andreas Huber | 1bd99498 | 2010-11-09 08:57:45 -0800 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2010 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | //#define LOG_NDEBUG 0 |
| 18 | #define LOG_TAG "VBRISeeker" |
| 19 | #include <utils/Log.h> |
| 20 | |
| 21 | #include "include/VBRISeeker.h" |
| 22 | |
| 23 | #include "include/MP3Extractor.h" |
| 24 | |
| 25 | #include <media/stagefright/foundation/ADebug.h> |
| 26 | #include <media/stagefright/DataSource.h> |
| 27 | #include <media/stagefright/Utils.h> |
| 28 | |
| 29 | namespace android { |
| 30 | |
| 31 | static uint32_t U24_AT(const uint8_t *ptr) { |
| 32 | return ptr[0] << 16 | ptr[1] << 8 | ptr[2]; |
| 33 | } |
| 34 | |
| 35 | // static |
| 36 | sp<VBRISeeker> VBRISeeker::CreateFromSource( |
James Dong | b1262a8 | 2010-11-16 14:04:54 -0800 | [diff] [blame] | 37 | const sp<DataSource> &source, off64_t post_id3_pos) { |
| 38 | off64_t pos = post_id3_pos; |
Andreas Huber | 1bd99498 | 2010-11-09 08:57:45 -0800 | [diff] [blame] | 39 | |
| 40 | uint8_t header[4]; |
| 41 | ssize_t n = source->readAt(pos, header, sizeof(header)); |
| 42 | if (n < (ssize_t)sizeof(header)) { |
| 43 | return NULL; |
| 44 | } |
| 45 | |
| 46 | uint32_t tmp = U32_AT(&header[0]); |
| 47 | size_t frameSize; |
| 48 | int sampleRate; |
| 49 | if (!MP3Extractor::get_mp3_frame_size(tmp, &frameSize, &sampleRate)) { |
| 50 | return NULL; |
| 51 | } |
| 52 | |
| 53 | // VBRI header follows 32 bytes after the header _ends_. |
| 54 | pos += sizeof(header) + 32; |
| 55 | |
| 56 | uint8_t vbriHeader[26]; |
| 57 | n = source->readAt(pos, vbriHeader, sizeof(vbriHeader)); |
| 58 | if (n < (ssize_t)sizeof(vbriHeader)) { |
| 59 | return NULL; |
| 60 | } |
| 61 | |
| 62 | if (memcmp(vbriHeader, "VBRI", 4)) { |
| 63 | return NULL; |
| 64 | } |
| 65 | |
| 66 | size_t numFrames = U32_AT(&vbriHeader[14]); |
| 67 | |
| 68 | int64_t durationUs = |
| 69 | numFrames * 1000000ll * (sampleRate >= 32000 ? 1152 : 576) / sampleRate; |
| 70 | |
| 71 | LOGV("duration = %.2f secs", durationUs / 1E6); |
| 72 | |
| 73 | size_t numEntries = U16_AT(&vbriHeader[18]); |
| 74 | size_t entrySize = U16_AT(&vbriHeader[22]); |
| 75 | size_t scale = U16_AT(&vbriHeader[20]); |
| 76 | |
| 77 | LOGV("%d entries, scale=%d, size_per_entry=%d", |
| 78 | numEntries, |
| 79 | scale, |
| 80 | entrySize); |
| 81 | |
| 82 | size_t totalEntrySize = numEntries * entrySize; |
| 83 | uint8_t *buffer = new uint8_t[totalEntrySize]; |
| 84 | |
| 85 | n = source->readAt(pos + sizeof(vbriHeader), buffer, totalEntrySize); |
| 86 | if (n < (ssize_t)totalEntrySize) { |
| 87 | delete[] buffer; |
| 88 | buffer = NULL; |
| 89 | |
| 90 | return NULL; |
| 91 | } |
| 92 | |
| 93 | sp<VBRISeeker> seeker = new VBRISeeker; |
| 94 | seeker->mBasePos = post_id3_pos; |
| 95 | seeker->mDurationUs = durationUs; |
| 96 | |
James Dong | b1262a8 | 2010-11-16 14:04:54 -0800 | [diff] [blame] | 97 | off64_t offset = post_id3_pos; |
Andreas Huber | 1bd99498 | 2010-11-09 08:57:45 -0800 | [diff] [blame] | 98 | for (size_t i = 0; i < numEntries; ++i) { |
| 99 | uint32_t numBytes; |
| 100 | switch (entrySize) { |
| 101 | case 1: numBytes = buffer[i]; break; |
| 102 | case 2: numBytes = U16_AT(buffer + 2 * i); break; |
| 103 | case 3: numBytes = U24_AT(buffer + 3 * i); break; |
| 104 | default: |
| 105 | { |
| 106 | CHECK_EQ(entrySize, 4u); |
| 107 | numBytes = U32_AT(buffer + 4 * i); break; |
| 108 | } |
| 109 | } |
| 110 | |
| 111 | numBytes *= scale; |
| 112 | |
| 113 | seeker->mSegments.push(numBytes); |
| 114 | |
| 115 | LOGV("entry #%d: %d offset 0x%08lx", i, numBytes, offset); |
| 116 | offset += numBytes; |
| 117 | } |
| 118 | |
| 119 | delete[] buffer; |
| 120 | buffer = NULL; |
| 121 | |
| 122 | LOGI("Found VBRI header."); |
| 123 | |
| 124 | return seeker; |
| 125 | } |
| 126 | |
| 127 | VBRISeeker::VBRISeeker() |
| 128 | : mDurationUs(-1) { |
| 129 | } |
| 130 | |
| 131 | bool VBRISeeker::getDuration(int64_t *durationUs) { |
| 132 | if (mDurationUs < 0) { |
| 133 | return false; |
| 134 | } |
| 135 | |
| 136 | *durationUs = mDurationUs; |
| 137 | |
| 138 | return true; |
| 139 | } |
| 140 | |
James Dong | b1262a8 | 2010-11-16 14:04:54 -0800 | [diff] [blame] | 141 | bool VBRISeeker::getOffsetForTime(int64_t *timeUs, off64_t *pos) { |
Andreas Huber | 1bd99498 | 2010-11-09 08:57:45 -0800 | [diff] [blame] | 142 | if (mDurationUs < 0) { |
| 143 | return false; |
| 144 | } |
| 145 | |
| 146 | int64_t segmentDurationUs = mDurationUs / mSegments.size(); |
| 147 | |
| 148 | int64_t nowUs = 0; |
| 149 | *pos = mBasePos; |
| 150 | size_t segmentIndex = 0; |
| 151 | while (segmentIndex < mSegments.size() && nowUs < *timeUs) { |
| 152 | nowUs += segmentDurationUs; |
| 153 | *pos += mSegments.itemAt(segmentIndex++); |
| 154 | } |
| 155 | |
| 156 | LOGV("getOffsetForTime %lld us => 0x%08lx", *timeUs, *pos); |
| 157 | |
| 158 | *timeUs = nowUs; |
| 159 | |
| 160 | return true; |
| 161 | } |
| 162 | |
| 163 | } // namespace android |
| 164 | |