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 | #include "include/XINGSeeker.h" |
| 18 | |
| 19 | #include <media/stagefright/DataSource.h> |
| 20 | #include <media/stagefright/Utils.h> |
| 21 | |
| 22 | namespace android { |
| 23 | |
| 24 | static bool parse_xing_header( |
James Dong | b1262a8 | 2010-11-16 14:04:54 -0800 | [diff] [blame] | 25 | const sp<DataSource> &source, off64_t first_frame_pos, |
Andreas Huber | 1bd99498 | 2010-11-09 08:57:45 -0800 | [diff] [blame] | 26 | int32_t *frame_number = NULL, int32_t *byte_number = NULL, |
| 27 | char *table_of_contents = NULL, int32_t *quality_indicator = NULL, |
| 28 | int64_t *duration = NULL); |
| 29 | |
| 30 | // static |
| 31 | sp<XINGSeeker> XINGSeeker::CreateFromSource( |
James Dong | b1262a8 | 2010-11-16 14:04:54 -0800 | [diff] [blame] | 32 | const sp<DataSource> &source, off64_t first_frame_pos) { |
Andreas Huber | 1bd99498 | 2010-11-09 08:57:45 -0800 | [diff] [blame] | 33 | sp<XINGSeeker> seeker = new XINGSeeker; |
| 34 | |
| 35 | seeker->mFirstFramePos = first_frame_pos; |
| 36 | |
| 37 | if (!parse_xing_header( |
| 38 | source, first_frame_pos, |
| 39 | NULL, &seeker->mSizeBytes, seeker->mTableOfContents, |
| 40 | NULL, &seeker->mDurationUs)) { |
| 41 | return NULL; |
| 42 | } |
| 43 | |
| 44 | LOGI("Found XING header."); |
| 45 | |
| 46 | return seeker; |
| 47 | } |
| 48 | |
| 49 | XINGSeeker::XINGSeeker() |
| 50 | : mDurationUs(-1), |
| 51 | mSizeBytes(0) { |
| 52 | } |
| 53 | |
| 54 | bool XINGSeeker::getDuration(int64_t *durationUs) { |
| 55 | if (mDurationUs < 0) { |
| 56 | return false; |
| 57 | } |
| 58 | |
| 59 | *durationUs = mDurationUs; |
| 60 | |
| 61 | return true; |
| 62 | } |
| 63 | |
James Dong | b1262a8 | 2010-11-16 14:04:54 -0800 | [diff] [blame] | 64 | bool XINGSeeker::getOffsetForTime(int64_t *timeUs, off64_t *pos) { |
Andreas Huber | 1bd99498 | 2010-11-09 08:57:45 -0800 | [diff] [blame] | 65 | if (mSizeBytes == 0 || mTableOfContents[0] <= 0 || mDurationUs < 0) { |
| 66 | return false; |
| 67 | } |
| 68 | |
| 69 | float percent = (float)(*timeUs) * 100 / mDurationUs; |
| 70 | float fx; |
| 71 | if( percent <= 0.0f ) { |
| 72 | fx = 0.0f; |
| 73 | } else if( percent >= 100.0f ) { |
| 74 | fx = 256.0f; |
| 75 | } else { |
| 76 | int a = (int)percent; |
| 77 | float fa, fb; |
| 78 | if ( a == 0 ) { |
| 79 | fa = 0.0f; |
| 80 | } else { |
| 81 | fa = (float)mTableOfContents[a-1]; |
| 82 | } |
| 83 | if ( a < 99 ) { |
| 84 | fb = (float)mTableOfContents[a]; |
| 85 | } else { |
| 86 | fb = 256.0f; |
| 87 | } |
| 88 | fx = fa + (fb-fa)*(percent-a); |
| 89 | } |
| 90 | |
| 91 | *pos = (int)((1.0f/256.0f)*fx*mSizeBytes) + mFirstFramePos; |
| 92 | |
| 93 | return true; |
| 94 | } |
| 95 | |
| 96 | static bool parse_xing_header( |
James Dong | b1262a8 | 2010-11-16 14:04:54 -0800 | [diff] [blame] | 97 | const sp<DataSource> &source, off64_t first_frame_pos, |
Andreas Huber | 1bd99498 | 2010-11-09 08:57:45 -0800 | [diff] [blame] | 98 | int32_t *frame_number, int32_t *byte_number, |
| 99 | char *table_of_contents, int32_t *quality_indicator, |
| 100 | int64_t *duration) { |
| 101 | if (frame_number) { |
| 102 | *frame_number = 0; |
| 103 | } |
| 104 | if (byte_number) { |
| 105 | *byte_number = 0; |
| 106 | } |
| 107 | if (table_of_contents) { |
| 108 | table_of_contents[0] = 0; |
| 109 | } |
| 110 | if (quality_indicator) { |
| 111 | *quality_indicator = 0; |
| 112 | } |
| 113 | if (duration) { |
| 114 | *duration = 0; |
| 115 | } |
| 116 | |
| 117 | uint8_t buffer[4]; |
| 118 | int offset = first_frame_pos; |
| 119 | if (source->readAt(offset, &buffer, 4) < 4) { // get header |
| 120 | return false; |
| 121 | } |
| 122 | offset += 4; |
| 123 | |
| 124 | uint8_t id, layer, sr_index, mode; |
| 125 | layer = (buffer[1] >> 1) & 3; |
| 126 | id = (buffer[1] >> 3) & 3; |
| 127 | sr_index = (buffer[2] >> 2) & 3; |
| 128 | mode = (buffer[3] >> 6) & 3; |
| 129 | if (layer == 0) { |
| 130 | return false; |
| 131 | } |
| 132 | if (id == 1) { |
| 133 | return false; |
| 134 | } |
| 135 | if (sr_index == 3) { |
| 136 | return false; |
| 137 | } |
| 138 | // determine offset of XING header |
| 139 | if(id&1) { // mpeg1 |
| 140 | if (mode != 3) offset += 32; |
| 141 | else offset += 17; |
| 142 | } else { // mpeg2 |
| 143 | if (mode != 3) offset += 17; |
| 144 | else offset += 9; |
| 145 | } |
| 146 | |
| 147 | if (source->readAt(offset, &buffer, 4) < 4) { // XING header ID |
| 148 | return false; |
| 149 | } |
| 150 | offset += 4; |
| 151 | // Check XING ID |
| 152 | if ((buffer[0] != 'X') || (buffer[1] != 'i') |
| 153 | || (buffer[2] != 'n') || (buffer[3] != 'g')) { |
| 154 | if ((buffer[0] != 'I') || (buffer[1] != 'n') |
| 155 | || (buffer[2] != 'f') || (buffer[3] != 'o')) { |
| 156 | return false; |
| 157 | } |
| 158 | } |
| 159 | |
| 160 | if (source->readAt(offset, &buffer, 4) < 4) { // flags |
| 161 | return false; |
| 162 | } |
| 163 | offset += 4; |
| 164 | uint32_t flags = U32_AT(buffer); |
| 165 | |
| 166 | if (flags & 0x0001) { // Frames field is present |
| 167 | if (source->readAt(offset, buffer, 4) < 4) { |
| 168 | return false; |
| 169 | } |
| 170 | if (frame_number) { |
| 171 | *frame_number = U32_AT(buffer); |
| 172 | } |
| 173 | int32_t frame = U32_AT(buffer); |
| 174 | // Samples per Frame: 1. index = MPEG Version ID, 2. index = Layer |
| 175 | const int samplesPerFrames[2][3] = |
| 176 | { |
| 177 | { 384, 1152, 576 }, // MPEG 2, 2.5: layer1, layer2, layer3 |
| 178 | { 384, 1152, 1152 }, // MPEG 1: layer1, layer2, layer3 |
| 179 | }; |
| 180 | // sampling rates in hertz: 1. index = MPEG Version ID, 2. index = sampling rate index |
| 181 | const int samplingRates[4][3] = |
| 182 | { |
| 183 | { 11025, 12000, 8000, }, // MPEG 2.5 |
| 184 | { 0, 0, 0, }, // reserved |
| 185 | { 22050, 24000, 16000, }, // MPEG 2 |
| 186 | { 44100, 48000, 32000, } // MPEG 1 |
| 187 | }; |
| 188 | if (duration) { |
| 189 | *duration = (int64_t)frame * samplesPerFrames[id&1][3-layer] * 1000000LL |
| 190 | / samplingRates[id][sr_index]; |
| 191 | } |
| 192 | offset += 4; |
| 193 | } |
| 194 | if (flags & 0x0002) { // Bytes field is present |
| 195 | if (byte_number) { |
| 196 | if (source->readAt(offset, buffer, 4) < 4) { |
| 197 | return false; |
| 198 | } |
| 199 | *byte_number = U32_AT(buffer); |
| 200 | } |
| 201 | offset += 4; |
| 202 | } |
| 203 | if (flags & 0x0004) { // TOC field is present |
| 204 | if (table_of_contents) { |
| 205 | if (source->readAt(offset + 1, table_of_contents, 99) < 99) { |
| 206 | return false; |
| 207 | } |
| 208 | } |
| 209 | offset += 100; |
| 210 | } |
| 211 | if (flags & 0x0008) { // Quality indicator field is present |
| 212 | if (quality_indicator) { |
| 213 | if (source->readAt(offset, buffer, 4) < 4) { |
| 214 | return false; |
| 215 | } |
| 216 | *quality_indicator = U32_AT(buffer); |
| 217 | } |
| 218 | } |
| 219 | return true; |
| 220 | } |
| 221 | |
| 222 | } // namespace android |
| 223 | |