MediaSource.h revision 79e23b41fad961008bfde6e26b3c6f86878ca69d 
1/*
2 * Copyright (C) 2009 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#ifndef MEDIA_SOURCE_H_
18
19#define MEDIA_SOURCE_H_
20
21#include <sys/types.h>
22
23#include <media/stagefright/MediaErrors.h>
24#include <utils/RefBase.h>
25
26namespace android {
27
28class MediaBuffer;
29class MetaData;
30
31struct MediaSource : public RefBase {
32    MediaSource();
33
34    // To be called before any other methods on this object, except
35    // getFormat().
36    virtual status_t start(MetaData *params = NULL) = 0;
37
38    // Any blocking read call returns immediately with a result of NO_INIT.
39    // It is an error to call any methods other than start after this call
40    // returns. Any buffers the object may be holding onto at the time of
41    // the stop() call are released.
42    // Also, it is imperative that any buffers output by this object and
43    // held onto by callers be released before a call to stop() !!!
44    virtual status_t stop() = 0;
45
46    // Returns the format of the data output by this media source.
47    virtual sp<MetaData> getFormat() = 0;
48
49    struct ReadOptions;
50
51    // Returns a new buffer of data. Call blocks until a
52    // buffer is available, an error is encountered of the end of the stream
53    // is reached.
54    // End of stream is signalled by a result of ERROR_END_OF_STREAM.
55    // A result of INFO_FORMAT_CHANGED indicates that the format of this
56    // MediaSource has changed mid-stream, the client can continue reading
57    // but should be prepared for buffers of the new configuration.
58    virtual status_t read(
59            MediaBuffer **buffer, const ReadOptions *options = NULL) = 0;
60
61    // Options that modify read() behaviour. The default is to
62    // a) not request a seek
63    // b) not be late, i.e. lateness_us = 0
64    struct ReadOptions {
65        enum SeekMode {
66            SEEK_PREVIOUS_SYNC,
67            SEEK_NEXT_SYNC,
68            SEEK_CLOSEST_SYNC,
69            SEEK_CLOSEST,
70        };
71
72        ReadOptions();
73
74        // Reset everything back to defaults.
75        void reset();
76
77        void setSeekTo(int64_t time_us, SeekMode mode = SEEK_CLOSEST_SYNC);
78        void clearSeekTo();
79        bool getSeekTo(int64_t *time_us, SeekMode *mode) const;
80
81        void setLateBy(int64_t lateness_us);
82        int64_t getLateBy() const;
83
84    private:
85        enum Options {
86            kSeekTo_Option      = 1,
87        };
88
89        uint32_t mOptions;
90        int64_t mSeekTimeUs;
91        SeekMode mSeekMode;
92        int64_t mLatenessUs;
93    };
94
95    // Causes this source to suspend pulling data from its upstream source
96    // until a subsequent read-with-seek. Currently only supported by
97    // OMXCodec.
98    virtual status_t pause() {
99        return ERROR_UNSUPPORTED;
100    }
101
102protected:
103    virtual ~MediaSource();
104
105private:
106    MediaSource(const MediaSource &);
107    MediaSource &operator=(const MediaSource &);
108};
109
110}  // namespace android
111
112#endif  // MEDIA_SOURCE_H_
113