diff options
| -rw-r--r-- | src/pcm_channels.h | 23 | ||||
| -rw-r--r-- | src/pcm_convert.h | 23 | ||||
| -rw-r--r-- | src/pcm_format.h | 23 | ||||
| -rw-r--r-- | src/pcm_mix.h | 13 | ||||
| -rw-r--r-- | src/pcm_resample.h | 35 | ||||
| -rw-r--r-- | src/pcm_volume.h | 14 |
6 files changed, 130 insertions, 1 deletions
diff --git a/src/pcm_channels.h b/src/pcm_channels.h index b4699ed8f..25c13d839 100644 --- a/src/pcm_channels.h +++ b/src/pcm_channels.h @@ -24,12 +24,35 @@ struct pcm_buffer; +/** + * Changes the number of channels in 16 bit PCM data. + * + * @param buffer the destination pcm_buffer object + * @param dest_channels the number of channels requested + * @param src_channels the number of channels in the source buffer + * @param src the source PCM buffer + * @param src_size the number of bytes in #src + * @param dest_size_r returns the number of bytes of the destination buffer + * @return the destination buffer + */ const int16_t * pcm_convert_channels_16(struct pcm_buffer *buffer, int8_t dest_channels, int8_t src_channels, const int16_t *src, size_t src_size, size_t *dest_size_r); +/** + * Changes the number of channels in 24 bit PCM data (aligned at 32 + * bit boundaries). + * + * @param buffer the destination pcm_buffer object + * @param dest_channels the number of channels requested + * @param src_channels the number of channels in the source buffer + * @param src the source PCM buffer + * @param src_size the number of bytes in #src + * @param dest_size_r returns the number of bytes of the destination buffer + * @return the destination buffer + */ const int32_t * pcm_convert_channels_24(struct pcm_buffer *buffer, int8_t dest_channels, diff --git a/src/pcm_convert.h b/src/pcm_convert.h index 18a1dbc49..35bbdad5c 100644 --- a/src/pcm_convert.h +++ b/src/pcm_convert.h @@ -25,6 +25,11 @@ struct audio_format; +/** + * This object is statically allocated (within another struct), and + * holds buffer allocations and the state for all kinds of PCM + * conversions. + */ struct pcm_convert_state { struct pcm_resample_state resample; @@ -37,10 +42,28 @@ struct pcm_convert_state { struct pcm_buffer channels_buffer; }; +/** + * Initializes a pcm_convert_state object. + */ void pcm_convert_init(struct pcm_convert_state *state); +/** + * Deinitializes a pcm_convert_state object and frees allocated + * memory. + */ void pcm_convert_deinit(struct pcm_convert_state *state); +/** + * Converts PCM data between two audio formats. + * + * @param state an initialized pcm_convert_state object + * @param src_format the source audio format + * @param src the source PCM buffer + * @param src_size the size of #src in bytes + * @param dest_format the requested destination audio format + * @param dest_size_r returns the number of bytes of the destination buffer + * @return the destination buffer + */ const void * pcm_convert(struct pcm_convert_state *state, const struct audio_format *src_format, diff --git a/src/pcm_format.h b/src/pcm_format.h index 628155dd4..32279faef 100644 --- a/src/pcm_format.h +++ b/src/pcm_format.h @@ -25,11 +25,34 @@ struct pcm_buffer; struct pcm_dither_24; +/** + * Converts PCM samples to 16 bit. If the source format is 24 bit, + * then dithering is applied. + * + * @param buffer a pcm_buffer object + * @param dither a pcm_dither_24 object for 24-to-16 conversion + * @param bits the number of in the source buffer + * @param src the source PCM buffer + * @param src_size the size of #src in bytes + * @param dest_size_r returns the number of bytes of the destination buffer + * @return the destination buffer + */ const int16_t * pcm_convert_to_16(struct pcm_buffer *buffer, struct pcm_dither_24 *dither, uint8_t bits, const void *src, size_t src_size, size_t *dest_size_r); +/** + * Converts PCM samples to 24 bit (32 bit alignment). + * + * @param buffer a pcm_buffer object + * @param dither a pcm_dither_24 object for 24-to-16 conversion + * @param bits the number of in the source buffer + * @param src the source PCM buffer + * @param src_size the size of #src in bytes + * @param dest_size_r returns the number of bytes of the destination buffer + * @return the destination buffer + */ const int32_t * pcm_convert_to_24(struct pcm_buffer *buffer, uint8_t bits, const void *src, diff --git a/src/pcm_mix.h b/src/pcm_mix.h index f3fe3c365..28b338f23 100644 --- a/src/pcm_mix.h +++ b/src/pcm_mix.h @@ -23,6 +23,19 @@ struct audio_format; +/* + * Linearly mixes two PCM buffers. Both must have the same length and + * the same audio format. The formula is: + * + * s1 := s1 * portion1 + s2 * (1 - portion1) + * + * @param buffer1 the first PCM buffer, and the destination buffer + * @param buffer2 the second PCM buffer + * @param size the size of both buffers in bytes + * @param format the audio format of both buffers + * @param portion1 a number between 0.0 and 1.0 specifying the portion + * of the first buffer in the mix; portion2 = (1.0 - portion1) + */ void pcm_mix(void *buffer1, const void *buffer2, size_t size, const struct audio_format *format, float portion1); diff --git a/src/pcm_resample.h b/src/pcm_resample.h index 66a746ae2..5042f4c99 100644 --- a/src/pcm_resample.h +++ b/src/pcm_resample.h @@ -31,6 +31,10 @@ #include <samplerate.h> #endif +/** + * This object is statically allocated (within another struct), and + * holds buffer allocations and the state for the resampler. + */ struct pcm_resample_state { #ifdef HAVE_LIBSAMPLERATE SRC_STATE *state; @@ -50,10 +54,29 @@ struct pcm_resample_state { struct pcm_buffer buffer; }; +/** + * Initializes a pcm_resample_state object. + */ void pcm_resample_init(struct pcm_resample_state *state); +/** + * Deinitializes a pcm_resample_state object and frees allocated + * memory. + */ void pcm_resample_deinit(struct pcm_resample_state *state); +/** + * Resamples 16 bit PCM data. + * + * @param state an initialized pcm_resample_state object + * @param channels the number of channels + * @param src_rate the source sample rate + * @param src the source PCM buffer + * @param src_size the size of #src in bytes + * @param dest_rate the requested destination sample rate + * @param dest_size_r returns the number of bytes of the destination buffer + * @return the destination buffer + */ const int16_t * pcm_resample_16(struct pcm_resample_state *state, uint8_t channels, @@ -62,6 +85,18 @@ pcm_resample_16(struct pcm_resample_state *state, unsigned dest_rate, size_t *dest_size_r); +/** + * Resamples 24 bit PCM data. + * + * @param state an initialized pcm_resample_state object + * @param channels the number of channels + * @param src_rate the source sample rate + * @param src the source PCM buffer + * @param src_size the size of #src in bytes + * @param dest_rate the requested destination sample rate + * @param dest_size_r returns the number of bytes of the destination buffer + * @return the destination buffer + */ const int32_t * pcm_resample_24(struct pcm_resample_state *state, uint8_t channels, diff --git a/src/pcm_volume.h b/src/pcm_volume.h index 44ced88af..1b5e7fb0e 100644 --- a/src/pcm_volume.h +++ b/src/pcm_volume.h @@ -40,6 +40,10 @@ pcm_float_to_volume(float volume) return volume * PCM_VOLUME_1 + 0.5; } +/** + * Returns the next volume dithering number, between -511 and +511. + * This number is taken from a global PRNG, see pcm_prng(). + */ static inline int pcm_volume_dither(void) { @@ -51,8 +55,16 @@ pcm_volume_dither(void) return (r & 511) - ((r >> 9) & 511); } +/** + * Adjust the volume of the specified PCM buffer. + * + * @param buffer the PCM buffer + * @param length the length of the PCM buffer + * @param format the audio format of the PCM buffer + * @param volume the volume between 0 and #PCM_VOLUME_1 + */ void -pcm_volume(void *buffer, int bufferSize, +pcm_volume(void *buffer, int length, const struct audio_format *format, int volume); |