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1 /* Copyright (c) 2013 The Chromium OS Authors. All rights reserved.
2  * Use of this source code is governed by a BSD-style license that can be
3  * found in the LICENSE file.
4  */
5 
6 #ifndef CRAS_A2DP_INFO_H_
7 #define CRAS_A2DP_INFO_H_
8 
9 #include "a2dp-codecs.h"
10 
11 #define A2DP_BUF_SIZE_BYTES 1024
12 
13 /* Represents the codec and encoded state of a2dp iodev.
14  * Members:
15  *    codec - The codec used to encode PCM buffer to a2dp buffer.
16  *    a2dp_buf - The buffer to hold encoded frames.
17  *    codesize - Size of a SBC frame in bytes.
18  *    frame_length - Size of an encoded SBC frame in bytes.
19  *    frame_count - Queued SBC frame count currently in a2dp buffer.
20  *    seq_num - Sequence number in rtp header.
21  *    samples - Queued PCM frame count currently in a2dp buffer.
22  *    nsamples - Cumulative number of encoded PCM frames.
23  *    a2dp_buf_used - Used a2dp buffer counter in bytes.
24  */
25 struct a2dp_info {
26 	struct cras_audio_codec *codec;
27 	uint8_t a2dp_buf[A2DP_BUF_SIZE_BYTES];
28 	int codesize;
29 	int frame_length;
30 	int frame_count;
31 	uint16_t seq_num;
32 	int samples;
33 	int nsamples;
34 	size_t a2dp_buf_used;
35 };
36 
37 /*
38  * Set up codec for given sbc capability.
39  */
40 int init_a2dp(struct a2dp_info *a2dp, a2dp_sbc_t *sbc);
41 
42 /*
43  * Destroys an a2dp_info.
44  */
45 void destroy_a2dp(struct a2dp_info *a2dp);
46 
47 /*
48  * Gets the codesize of the SBC codec.
49  */
50 int a2dp_codesize(struct a2dp_info *a2dp);
51 
52 /*
53  * Gets original size of a2dp encoded bytes.
54  */
55 int a2dp_block_size(struct a2dp_info *a2dp, int encoded_bytes);
56 
57 /*
58  * Gets the number of queued frames in a2dp_info.
59  */
60 int a2dp_queued_frames(const struct a2dp_info *a2dp);
61 
62 /*
63  * Drains queued samples in a2dp_info.
64  */
65 void a2dp_drain(struct a2dp_info *a2dp);
66 
67 /*
68  * Encodes samples using the codec for this a2dp instance, returns the number of
69  * pcm bytes processed.
70  * Args:
71  *    a2dp: The a2dp info object.
72  *    pcm_buf: The buffer of pcm samples.
73  *    pcm_buf_size: Size of the pcm buffer.
74  *    format_bytes: Number of bytes per sample.
75  *    link_mtu: The maximum transmit unit.
76  */
77 int a2dp_encode(struct a2dp_info *a2dp, const void *pcm_buf, int pcm_buf_size,
78 		int format_bytes, size_t link_mtu);
79 
80 /*
81  * Writes samples using a2dp, returns number of frames written.
82  * Args:
83  *    a2dp: The a2dp info object.
84  *    stream_fd: The file descriptor to send stream to.
85  *    link_mtu: The maximum transmit unit.
86  */
87 int a2dp_write(struct a2dp_info *a2dp, int stream_fd, size_t link_mtu);
88 
89 #endif /* CRAS_A2DP_INFO_H_ */
90