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samplefmt.h
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1 /*
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5  * modify it under the terms of the GNU Lesser General Public
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8  *
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12  * Lesser General Public License for more details.
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15  * License along with FFmpeg; if not, write to the Free Software
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17  */
18 
19 #ifndef AVUTIL_SAMPLEFMT_H
20 #define AVUTIL_SAMPLEFMT_H
21 
22 #include <stdint.h>
23 
24 #include "avutil.h"
25 #include "attributes.h"
26 
27 /**
28  * Audio Sample Formats
29  *
30  * @par
31  * The data described by the sample format is always in native-endian order.
32  * Sample values can be expressed by native C types, hence the lack of a signed
33  * 24-bit sample format even though it is a common raw audio data format.
34  *
35  * @par
36  * The floating-point formats are based on full volume being in the range
37  * [-1.0, 1.0]. Any values outside this range are beyond full volume level.
38  *
39  * @par
40  * The data layout as used in av_samples_fill_arrays() and elsewhere in FFmpeg
41  * (such as AVFrame in libavcodec) is as follows:
42  *
43  * For planar sample formats, each audio channel is in a separate data plane,
44  * and linesize is the buffer size, in bytes, for a single plane. All data
45  * planes must be the same size. For packed sample formats, only the first data
46  * plane is used, and samples for each channel are interleaved. In this case,
47  * linesize is the buffer size, in bytes, for the 1 plane.
48  */
51  AV_SAMPLE_FMT_U8, ///< unsigned 8 bits
52  AV_SAMPLE_FMT_S16, ///< signed 16 bits
53  AV_SAMPLE_FMT_S32, ///< signed 32 bits
54  AV_SAMPLE_FMT_FLT, ///< float
55  AV_SAMPLE_FMT_DBL, ///< double
56 
57  AV_SAMPLE_FMT_U8P, ///< unsigned 8 bits, planar
58  AV_SAMPLE_FMT_S16P, ///< signed 16 bits, planar
59  AV_SAMPLE_FMT_S32P, ///< signed 32 bits, planar
60  AV_SAMPLE_FMT_FLTP, ///< float, planar
61  AV_SAMPLE_FMT_DBLP, ///< double, planar
62 
63  AV_SAMPLE_FMT_NB ///< Number of sample formats. DO NOT USE if linking dynamically
64 };
65 
66 /**
67  * Return the name of sample_fmt, or NULL if sample_fmt is not
68  * recognized.
69  */
70 const char *av_get_sample_fmt_name(enum AVSampleFormat sample_fmt);
71 
72 /**
73  * Return a sample format corresponding to name, or AV_SAMPLE_FMT_NONE
74  * on error.
75  */
76 enum AVSampleFormat av_get_sample_fmt(const char *name);
77 
78 /**
79  * Return the planar<->packed alternative form of the given sample format, or
80  * AV_SAMPLE_FMT_NONE on error. If the passed sample_fmt is already in the
81  * requested planar/packed format, the format returned is the same as the
82  * input.
83  */
84 enum AVSampleFormat av_get_alt_sample_fmt(enum AVSampleFormat sample_fmt, int planar);
85 
86 /**
87  * Get the packed alternative form of the given sample format.
88  *
89  * If the passed sample_fmt is already in packed format, the format returned is
90  * the same as the input.
91  *
92  * @return the packed alternative form of the given sample format or
93  AV_SAMPLE_FMT_NONE on error.
94  */
96 
97 /**
98  * Get the planar alternative form of the given sample format.
99  *
100  * If the passed sample_fmt is already in planar format, the format returned is
101  * the same as the input.
102  *
103  * @return the planar alternative form of the given sample format or
104  AV_SAMPLE_FMT_NONE on error.
105  */
107 
108 /**
109  * Generate a string corresponding to the sample format with
110  * sample_fmt, or a header if sample_fmt is negative.
111  *
112  * @param buf the buffer where to write the string
113  * @param buf_size the size of buf
114  * @param sample_fmt the number of the sample format to print the
115  * corresponding info string, or a negative value to print the
116  * corresponding header.
117  * @return the pointer to the filled buffer or NULL if sample_fmt is
118  * unknown or in case of other errors
119  */
120 char *av_get_sample_fmt_string(char *buf, int buf_size, enum AVSampleFormat sample_fmt);
121 
122 #if FF_API_GET_BITS_PER_SAMPLE_FMT
123 /**
124  * @deprecated Use av_get_bytes_per_sample() instead.
125  */
127 int av_get_bits_per_sample_fmt(enum AVSampleFormat sample_fmt);
128 #endif
129 
130 /**
131  * Return number of bytes per sample.
132  *
133  * @param sample_fmt the sample format
134  * @return number of bytes per sample or zero if unknown for the given
135  * sample format
136  */
137 int av_get_bytes_per_sample(enum AVSampleFormat sample_fmt);
138 
139 /**
140  * Check if the sample format is planar.
141  *
142  * @param sample_fmt the sample format to inspect
143  * @return 1 if the sample format is planar, 0 if it is interleaved
144  */
145 int av_sample_fmt_is_planar(enum AVSampleFormat sample_fmt);
146 
147 /**
148  * Get the required buffer size for the given audio parameters.
149  *
150  * @param[out] linesize calculated linesize, may be NULL
151  * @param nb_channels the number of channels
152  * @param nb_samples the number of samples in a single channel
153  * @param sample_fmt the sample format
154  * @param align buffer size alignment (0 = default, 1 = no alignment)
155  * @return required buffer size, or negative error code on failure
156  */
157 int av_samples_get_buffer_size(int *linesize, int nb_channels, int nb_samples,
158  enum AVSampleFormat sample_fmt, int align);
159 
160 /**
161  * Fill plane data pointers and linesize for samples with sample
162  * format sample_fmt.
163  *
164  * The audio_data array is filled with the pointers to the samples data planes:
165  * for planar, set the start point of each channel's data within the buffer,
166  * for packed, set the start point of the entire buffer only.
167  *
168  * The value pointed to by linesize is set to the aligned size of each
169  * channel's data buffer for planar layout, or to the aligned size of the
170  * buffer for all channels for packed layout.
171  *
172  * The buffer in buf must be big enough to contain all the samples
173  * (use av_samples_get_buffer_size() to compute its minimum size),
174  * otherwise the audio_data pointers will point to invalid data.
175  *
176  * @see enum AVSampleFormat
177  * The documentation for AVSampleFormat describes the data layout.
178  *
179  * @param[out] audio_data array to be filled with the pointer for each channel
180  * @param[out] linesize calculated linesize, may be NULL
181  * @param buf the pointer to a buffer containing the samples
182  * @param nb_channels the number of channels
183  * @param nb_samples the number of samples in a single channel
184  * @param sample_fmt the sample format
185  * @param align buffer size alignment (0 = default, 1 = no alignment)
186  * @return >=0 on success or a negative error code on failure
187  * @todo return minimum size in bytes required for the buffer in case
188  * of success at the next bump
189  */
190 int av_samples_fill_arrays(uint8_t **audio_data, int *linesize,
191  const uint8_t *buf,
192  int nb_channels, int nb_samples,
193  enum AVSampleFormat sample_fmt, int align);
194 
195 /**
196  * Allocate a samples buffer for nb_samples samples, and fill data pointers and
197  * linesize accordingly.
198  * The allocated samples buffer can be freed by using av_freep(&audio_data[0])
199  * Allocated data will be initialized to silence.
200  *
201  * @see enum AVSampleFormat
202  * The documentation for AVSampleFormat describes the data layout.
203  *
204  * @param[out] audio_data array to be filled with the pointer for each channel
205  * @param[out] linesize aligned size for audio buffer(s), may be NULL
206  * @param nb_channels number of audio channels
207  * @param nb_samples number of samples per channel
208  * @param align buffer size alignment (0 = default, 1 = no alignment)
209  * @return >=0 on success or a negative error code on failure
210  * @todo return the size of the allocated buffer in case of success at the next bump
211  * @see av_samples_fill_arrays()
212  */
213 int av_samples_alloc(uint8_t **audio_data, int *linesize, int nb_channels,
214  int nb_samples, enum AVSampleFormat sample_fmt, int align);
215 
216 /**
217  * Copy samples from src to dst.
218  *
219  * @param dst destination array of pointers to data planes
220  * @param src source array of pointers to data planes
221  * @param dst_offset offset in samples at which the data will be written to dst
222  * @param src_offset offset in samples at which the data will be read from src
223  * @param nb_samples number of samples to be copied
224  * @param nb_channels number of audio channels
225  * @param sample_fmt audio sample format
226  */
227 int av_samples_copy(uint8_t **dst, uint8_t * const *src, int dst_offset,
228  int src_offset, int nb_samples, int nb_channels,
229  enum AVSampleFormat sample_fmt);
230 
231 /**
232  * Fill an audio buffer with silence.
233  *
234  * @param audio_data array of pointers to data planes
235  * @param offset offset in samples at which to start filling
236  * @param nb_samples number of samples to fill
237  * @param nb_channels number of audio channels
238  * @param sample_fmt audio sample format
239  */
240 int av_samples_set_silence(uint8_t **audio_data, int offset, int nb_samples,
241  int nb_channels, enum AVSampleFormat sample_fmt);
242 
243 #endif /* AVUTIL_SAMPLEFMT_H */