Home | History | Annotate | Download | only in server 
      1 /* Copyright (c) 2014 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_AUDIO_AREA_H_
      7 #define CRAS_AUDIO_AREA_H_
      8 
      9 #include <stdint.h>
     10 
     11 #include "cras_audio_format.h"
     12 
     13 /*
     14  * Descriptor of the memory area holding a channel of audio.
     15  * Members:
     16  *    ch_set - Bit set of channels this channel area could map to.
     17  *    step_bytes - The number of bytes between adjacent samples.
     18  *    buf - A pointer to the start address of this area.
     19  */
     20 struct cras_channel_area {
     21 	unsigned int ch_set;
     22 	unsigned int step_bytes;
     23 	uint8_t *buf;
     24 };
     25 
     26 /*
     27  * Descriptor of the memory area that provides various access to audio channels.
     28  * Members:
     29  *    frames - The size of the audio buffer in frames.
     30  *    num_channels - The number of channels in the audio area.
     31  *    channels - array of channel areas.
     32  */
     33 struct cras_audio_area {
     34 	unsigned int frames;
     35 	unsigned int num_channels;
     36 	struct cras_channel_area channels[];
     37 };
     38 
     39 /*
     40  * Sets the channel bit for a channel area.
     41  * Args:
     42  *    ca - the channel area to set channel bit set.
     43  *    channel - the channel bit to add to the channel area.
     44  */
     45 static
     46 inline void channel_area_set_channel(struct cras_channel_area *ca,
     47 				     enum CRAS_CHANNEL channel)
     48 {
     49 	ca->ch_set |= (1 << channel);
     50 }
     51 
     52 /*
     53  * Creates a cras_audio_area.
     54  * Args:
     55  *    num_channels - The number of channels in the audio area.
     56 */
     57 struct cras_audio_area *cras_audio_area_create(int num_channels);
     58 
     59 /*
     60  * Copies a cras_audio_area to another cras_audio_area with given offset.
     61  * Args:
     62  *    dst - The destination audio area.
     63  *    dst_offset - The offset of dst audio area in frames.
     64  *    format - The format of dst area.
     65  *    src - The source audio area.
     66  *    src_offset - The offset of src audio area in frames.
     67  *    software_gain_scaler - The software gain scaler needed.
     68  * Returns the number of frames copied.
     69  */
     70 unsigned int cras_audio_area_copy(const struct cras_audio_area *dst,
     71 				  unsigned int dst_offset,
     72 				  const struct cras_audio_format *dst_fmt,
     73 				  const struct cras_audio_area *src,
     74 				  unsigned int src_offset,
     75 				  float software_gain_scaler);
     76 
     77 /*
     78  * Destroys a cras_audio_area.
     79  * Args:
     80  *    area - the audio area to destroy
     81  */
     82 void cras_audio_area_destroy(struct cras_audio_area *area);
     83 
     84 /*
     85  * Configures the channel types based on the audio format.
     86  * Args:
     87  *    area - The audio area created with cras_audio_area_create.
     88  *    fmt - The format to use to configure the channels.
     89  */
     90 void cras_audio_area_config_channels(struct cras_audio_area *area,
     91 				     const struct cras_audio_format *fmt);
     92 
     93 /*
     94  * Sets the buffer pointers for each channel.
     95  */
     96 void cras_audio_area_config_buf_pointers(struct cras_audio_area *area,
     97 					 const struct cras_audio_format *fmt,
     98 					 uint8_t *base_buffer);
     99 
    100 #endif /* CRAS_AUDIO_AREA_H_ */
    101