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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 
     26 namespace android {
     27 
     28 class MediaBuffer;
     29 class MetaData;
     30 
     31 struct 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         // Option allows encoder to skip some frames until the specified
     82         // time stamp.
     83         // To prevent from being abused, when the skipFrame timestamp is
     84         // found to be more than 1 second later than the current timestamp,
     85         // an error will be returned from read().
     86         void clearSkipFrame();
     87         bool getSkipFrame(int64_t *timeUs) const;
     88         void setSkipFrame(int64_t timeUs);
     89 
     90         void setLateBy(int64_t lateness_us);
     91         int64_t getLateBy() const;
     92 
     93     private:
     94         enum Options {
     95             // Bit map
     96             kSeekTo_Option      = 1,
     97             kSkipFrame_Option   = 2,
     98         };
     99 
    100         uint32_t mOptions;
    101         int64_t mSeekTimeUs;
    102         SeekMode mSeekMode;
    103         int64_t mLatenessUs;
    104 
    105         int64_t mSkipFrameUntilTimeUs;
    106     };
    107 
    108     // Causes this source to suspend pulling data from its upstream source
    109     // until a subsequent read-with-seek. Currently only supported by
    110     // OMXCodec.
    111     virtual status_t pause() {
    112         return ERROR_UNSUPPORTED;
    113     }
    114 
    115 protected:
    116     virtual ~MediaSource();
    117 
    118 private:
    119     MediaSource(const MediaSource &);
    120     MediaSource &operator=(const MediaSource &);
    121 };
    122 
    123 }  // namespace android
    124 
    125 #endif  // MEDIA_SOURCE_H_
    126