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      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 #include <utils/Vector.h>
     26 
     27 namespace android {
     28 
     29 class MediaBuffer;
     30 class MetaData;
     31 
     32 struct MediaSource : public virtual RefBase {
     33     MediaSource();
     34 
     35     // To be called before any other methods on this object, except
     36     // getFormat().
     37     virtual status_t start(MetaData *params = NULL) = 0;
     38 
     39     // Any blocking read call returns immediately with a result of NO_INIT.
     40     // It is an error to call any methods other than start after this call
     41     // returns. Any buffers the object may be holding onto at the time of
     42     // the stop() call are released.
     43     // Also, it is imperative that any buffers output by this object and
     44     // held onto by callers be released before a call to stop() !!!
     45     virtual status_t stop() = 0;
     46 
     47     // Returns the format of the data output by this media source.
     48     virtual sp<MetaData> getFormat() = 0;
     49 
     50     struct ReadOptions;
     51 
     52     // Returns a new buffer of data. Call blocks until a
     53     // buffer is available, an error is encountered of the end of the stream
     54     // is reached.
     55     // End of stream is signalled by a result of ERROR_END_OF_STREAM.
     56     // A result of INFO_FORMAT_CHANGED indicates that the format of this
     57     // MediaSource has changed mid-stream, the client can continue reading
     58     // but should be prepared for buffers of the new configuration.
     59     virtual status_t read(
     60             MediaBuffer **buffer, const ReadOptions *options = NULL) = 0;
     61 
     62     // Options that modify read() behaviour. The default is to
     63     // a) not request a seek
     64     // b) not be late, i.e. lateness_us = 0
     65     struct ReadOptions {
     66         enum SeekMode {
     67             SEEK_PREVIOUS_SYNC,
     68             SEEK_NEXT_SYNC,
     69             SEEK_CLOSEST_SYNC,
     70             SEEK_CLOSEST,
     71         };
     72 
     73         ReadOptions();
     74 
     75         // Reset everything back to defaults.
     76         void reset();
     77 
     78         void setSeekTo(int64_t time_us, SeekMode mode = SEEK_CLOSEST_SYNC);
     79         void clearSeekTo();
     80         bool getSeekTo(int64_t *time_us, SeekMode *mode) const;
     81 
     82         void setLateBy(int64_t lateness_us);
     83         int64_t getLateBy() const;
     84 
     85     private:
     86         enum Options {
     87             kSeekTo_Option      = 1,
     88         };
     89 
     90         uint32_t mOptions;
     91         int64_t mSeekTimeUs;
     92         SeekMode mSeekMode;
     93         int64_t mLatenessUs;
     94     };
     95 
     96     // Causes this source to suspend pulling data from its upstream source
     97     // until a subsequent read-with-seek. Currently only supported by
     98     // OMXCodec.
     99     virtual status_t pause() {
    100         return ERROR_UNSUPPORTED;
    101     }
    102 
    103     // The consumer of this media source requests that the given buffers
    104     // are to be returned exclusively in response to read calls.
    105     // This will be called after a successful start() and before the
    106     // first read() call.
    107     // Callee assumes ownership of the buffers if no error is returned.
    108     virtual status_t setBuffers(const Vector<MediaBuffer *> &buffers) {
    109         return ERROR_UNSUPPORTED;
    110     }
    111 
    112 protected:
    113     virtual ~MediaSource();
    114 
    115 private:
    116     MediaSource(const MediaSource &);
    117     MediaSource &operator=(const MediaSource &);
    118 };
    119 
    120 }  // namespace android
    121 
    122 #endif  // MEDIA_SOURCE_H_
    123