1d91dc5a0602f54fc0d4d2187f37b5b8169bb62c3Dongwon Kang/*
2
3 * Copyright (C) 2009 The Android Open Source Project
4 *
5 * Licensed under the Apache License, Version 2.0 (the "License");
6 * you may not use this file except in compliance with the License.
7 * You may obtain a copy of the License at
8 *
9 *      http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18#ifndef MEDIA_SOURCE_H_
19
20#define MEDIA_SOURCE_H_
21
22#include <sys/types.h>
23
24#include <media/stagefright/MediaErrors.h>
25#include <media/stagefright/MetaData.h>
26#include <utils/RefBase.h>
27
28#include <media/MediaTrack.h>
29
30namespace android {
31
32class MediaBuffer;
33
34struct MediaSource : public virtual RefBase {
35    MediaSource();
36
37    // To be called before any other methods on this object, except
38    // getFormat().
39    virtual status_t start(MetaData *params = NULL) = 0;
40
41    // Any blocking read call returns immediately with a result of NO_INIT.
42    // It is an error to call any methods other than start after this call
43    // returns. Any buffers the object may be holding onto at the time of
44    // the stop() call are released.
45    // Also, it is imperative that any buffers output by this object and
46    // held onto by callers be released before a call to stop() !!!
47    virtual status_t stop() = 0;
48
49    // Returns the format of the data output by this media source.
50    virtual sp<MetaData> getFormat() = 0;
51
52    // Options that modify read() behaviour. The default is to
53    // a) not request a seek
54    // b) not be late, i.e. lateness_us = 0
55    typedef MediaTrack::ReadOptions ReadOptions;
56
57    // Returns a new buffer of data. Call blocks until a
58    // buffer is available, an error is encountered of the end of the stream
59    // is reached.
60    // End of stream is signalled by a result of ERROR_END_OF_STREAM.
61    // A result of INFO_FORMAT_CHANGED indicates that the format of this
62    // MediaSource has changed mid-stream, the client can continue reading
63    // but should be prepared for buffers of the new configuration.
64    virtual status_t read(
65            MediaBufferBase **buffer, const ReadOptions *options = NULL) = 0;
66
67    // Causes this source to suspend pulling data from its upstream source
68    // until a subsequent read-with-seek. This is currently not supported
69    // as such by any source. E.g. MediaCodecSource does not suspend its
70    // upstream source, and instead discard upstream data while paused.
71    virtual status_t pause() {
72        return ERROR_UNSUPPORTED;
73    }
74
75    // The consumer of this media source requests the source stops sending
76    // buffers with timestamp larger than or equal to stopTimeUs. stopTimeUs
77    // must be in the same time base as the startTime passed in start(). If
78    // source does not support this request, ERROR_UNSUPPORTED will be returned.
79    // If stopTimeUs is invalid, BAD_VALUE will be returned. This could be
80    // called at any time even before source starts and it could be called
81    // multiple times. Setting stopTimeUs to be -1 will effectively cancel the stopTimeUs
82    // set previously. If stopTimeUs is larger than or equal to last buffer's timestamp,
83    // source will start to drop buffer when it gets a buffer with timestamp larger
84    // than or equal to stopTimeUs. If stopTimeUs is smaller than or equal to last
85    // buffer's timestamp, source will drop all the incoming buffers immediately.
86    // After setting stopTimeUs, source may still stop sending buffers with timestamp
87    // less than stopTimeUs if it is stopped by the consumer.
88    virtual status_t setStopTimeUs(int64_t /* stopTimeUs */) {
89        return ERROR_UNSUPPORTED;
90    }
91
92protected:
93    virtual ~MediaSource();
94
95private:
96    MediaSource(const MediaSource &);
97    MediaSource &operator=(const MediaSource &);
98};
99
100}  // namespace android
101
102#endif  // MEDIA_SOURCE_H_
103