MPEG2TSExtractor.cpp revision 2a4d22d79e927f2245537921e10fc5fda1c47a29 
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 "MPEG2TSExtractor"
19#include <utils/Log.h>
20
21#include "include/MPEG2TSExtractor.h"
22
23#include <media/stagefright/DataSource.h>
24#include <media/stagefright/MediaDefs.h>
25#include <media/stagefright/MediaErrors.h>
26#include <media/stagefright/MediaSource.h>
27#include <media/stagefright/MetaData.h>
28#include <utils/String8.h>
29
30#include "AnotherPacketSource.h"
31#include "ATSParser.h"
32
33namespace android {
34
35static const size_t kTSPacketSize = 188;
36
37struct MPEG2TSSource : public MediaSource {
38    MPEG2TSSource(
39            const sp<MPEG2TSExtractor> &extractor,
40            const sp<AnotherPacketSource> &impl);
41
42    virtual status_t start(MetaData *params = NULL);
43    virtual status_t stop();
44    virtual sp<MetaData> getFormat();
45
46    virtual status_t read(
47            MediaBuffer **buffer, const ReadOptions *options = NULL);
48
49private:
50    sp<MPEG2TSExtractor> mExtractor;
51    sp<AnotherPacketSource> mImpl;
52
53    DISALLOW_EVIL_CONSTRUCTORS(MPEG2TSSource);
54};
55
56MPEG2TSSource::MPEG2TSSource(
57        const sp<MPEG2TSExtractor> &extractor,
58        const sp<AnotherPacketSource> &impl)
59    : mExtractor(extractor),
60      mImpl(impl) {
61}
62
63status_t MPEG2TSSource::start(MetaData *params) {
64    return mImpl->start(params);
65}
66
67status_t MPEG2TSSource::stop() {
68    return mImpl->stop();
69}
70
71sp<MetaData> MPEG2TSSource::getFormat() {
72    return mImpl->getFormat();
73}
74
75status_t MPEG2TSSource::read(
76        MediaBuffer **out, const ReadOptions *options) {
77    *out = NULL;
78
79    status_t finalResult;
80    while (!mImpl->hasBufferAvailable(&finalResult)) {
81        if (finalResult != OK) {
82            return ERROR_END_OF_STREAM;
83        }
84
85        status_t err = mExtractor->feedMore();
86        if (err != OK) {
87            mImpl->signalEOS(err);
88        }
89    }
90
91    return mImpl->read(out, options);
92}
93
94////////////////////////////////////////////////////////////////////////////////
95
96MPEG2TSExtractor::MPEG2TSExtractor(const sp<DataSource> &source)
97    : mDataSource(source),
98      mParser(new ATSParser),
99      mOffset(0) {
100    init();
101}
102
103size_t MPEG2TSExtractor::countTracks() {
104    return mSourceImpls.size();
105}
106
107sp<MediaSource> MPEG2TSExtractor::getTrack(size_t index) {
108    if (index >= mSourceImpls.size()) {
109        return NULL;
110    }
111
112    return new MPEG2TSSource(this, mSourceImpls.editItemAt(index));
113}
114
115sp<MetaData> MPEG2TSExtractor::getTrackMetaData(
116        size_t index, uint32_t flags) {
117    return index < mSourceImpls.size()
118        ? mSourceImpls.editItemAt(index)->getFormat() : NULL;
119}
120
121sp<MetaData> MPEG2TSExtractor::getMetaData() {
122    sp<MetaData> meta = new MetaData;
123    meta->setCString(kKeyMIMEType, MEDIA_MIMETYPE_CONTAINER_MPEG2TS);
124
125    return meta;
126}
127
128void MPEG2TSExtractor::init() {
129    bool haveAudio = false;
130    bool haveVideo = false;
131    int numPacketsParsed = 0;
132
133    while (feedMore() == OK) {
134        ATSParser::SourceType type;
135        if (haveAudio && haveVideo) {
136            break;
137        }
138        if (!haveVideo) {
139            sp<AnotherPacketSource> impl =
140                (AnotherPacketSource *)mParser->getSource(
141                        ATSParser::AVC_VIDEO).get();
142
143            if (impl != NULL) {
144                haveVideo = true;
145                mSourceImpls.push(impl);
146            }
147        }
148
149        if (!haveAudio) {
150            sp<AnotherPacketSource> impl =
151                (AnotherPacketSource *)mParser->getSource(
152                        ATSParser::MPEG2ADTS_AUDIO).get();
153
154            if (impl != NULL) {
155                haveAudio = true;
156                mSourceImpls.push(impl);
157            }
158        }
159
160        if (++numPacketsParsed > 2500) {
161            break;
162        }
163    }
164
165    LOGI("haveAudio=%d, haveVideo=%d", haveAudio, haveVideo);
166}
167
168static bool isDiscontinuity(const uint8_t *data, ssize_t size) {
169    return size == 188 && data[0] == 0x00;
170}
171
172status_t MPEG2TSExtractor::feedMore() {
173    Mutex::Autolock autoLock(mLock);
174
175    uint8_t packet[kTSPacketSize];
176    ssize_t n = mDataSource->readAt(mOffset, packet, kTSPacketSize);
177
178    if (isDiscontinuity(packet, n)) {
179        LOGI("XXX discontinuity detected");
180        mParser->signalDiscontinuity();
181    } else if (n < (ssize_t)kTSPacketSize) {
182        return (n < 0) ? (status_t)n : ERROR_END_OF_STREAM;
183    } else {
184        mParser->feedTSPacket(packet, kTSPacketSize);
185    }
186
187    mOffset += n;
188
189    return OK;
190}
191
192////////////////////////////////////////////////////////////////////////////////
193
194bool SniffMPEG2TS(
195        const sp<DataSource> &source, String8 *mimeType, float *confidence,
196        sp<AMessage> *) {
197    for (int i = 0; i < 5; ++i) {
198        char header;
199        if (source->readAt(kTSPacketSize * i, &header, 1) != 1
200                || header != 0x47) {
201            return false;
202        }
203    }
204
205    *confidence = 0.1f;
206    mimeType->setTo(MEDIA_MIMETYPE_CONTAINER_MPEG2TS);
207
208    return true;
209}
210
211}  // namespace android
212