1 /*
2  * Copyright (C) 2012 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 SKIP_CUT_BUFFER_H_
18 
19 #define SKIP_CUT_BUFFER_H_
20 
21 #include <media/MediaCodecBuffer.h>
22 #include <media/stagefright/MediaBuffer.h>
23 #include <media/stagefright/foundation/ABuffer.h>
24 
25 namespace android {
26 
27 /**
28  * utility class to cut the start and end off a stream of data in MediaBuffers
29  *
30  */
31 class SkipCutBuffer: public RefBase {
32  public:
33     // 'skip' is the number of frames to skip from the beginning
34     // 'cut' is the number of frames to cut from the end
35     // 'num16BitChannels' is the number of channels, which are assumed to be 16 bit wide each
36     SkipCutBuffer(size_t skip, size_t cut, size_t num16Channels);
37 
38     // Submit one MediaBuffer for skipping and cutting. This may consume all or
39     // some of the data in the buffer, or it may add data to it.
40     // After this, the caller should continue processing the buffer as usual.
41     void submit(MediaBuffer *buffer);
42     void submit(const sp<ABuffer>& buffer);    // same as above, but with an ABuffer
43     void submit(const sp<MediaCodecBuffer>& buffer);    // same as above, but with an ABuffer
44     void clear();
45     size_t size(); // how many bytes are currently stored in the buffer
46 
47  protected:
48     virtual ~SkipCutBuffer();
49 
50  private:
51     void write(const char *src, size_t num);
52     size_t read(char *dst, size_t num);
53     template <typename T>
54     void submitInternal(const sp<T>& buffer);
55     int32_t mSkip;
56     int32_t mFrontPadding;
57     int32_t mBackPadding;
58     int32_t mWriteHead;
59     int32_t mReadHead;
60     int32_t mCapacity;
61     char* mCutBuffer;
62     DISALLOW_EVIL_CONSTRUCTORS(SkipCutBuffer);
63 };
64 
65 }  // namespace android
66 
67 #endif  // OMX_CODEC_H_
68