aboutsummaryrefslogtreecommitdiffhomepage
path: root/audio/format.c
blob: 8a13698ff7ad01f685a8a9deb1a408c9a818d6f2 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
/*
 * Copyright (C) 2005 Alex Beregszaszi
 *
 * This file is part of mpv.
 *
 * mpv is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * mpv is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with mpv.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <limits.h>

#include "common/common.h"
#include "format.h"

// number of bytes per sample, 0 if invalid/unknown
int af_fmt_to_bytes(int format)
{
    switch (af_fmt_from_planar(format)) {
    case AF_FORMAT_U8:      return 1;
    case AF_FORMAT_S16:     return 2;
    case AF_FORMAT_S32:     return 4;
    case AF_FORMAT_FLOAT:   return 4;
    case AF_FORMAT_DOUBLE:  return 8;
    }
    if (af_fmt_is_spdif(format))
        return 2;
    return 0;
}

// All formats are considered signed, except explicitly unsigned int formats.
bool af_fmt_is_unsigned(int format)
{
    return format == AF_FORMAT_U8 || format == AF_FORMAT_U8P;
}

bool af_fmt_is_float(int format)
{
    format = af_fmt_from_planar(format);
    return format == AF_FORMAT_FLOAT || format == AF_FORMAT_DOUBLE;
}

// true for both unsigned and signed ints
bool af_fmt_is_int(int format)
{
    return format && !af_fmt_is_spdif(format) && !af_fmt_is_float(format);
}

// false for interleaved and AF_FORMAT_UNKNOWN
bool af_fmt_is_planar(int format)
{
    return format && af_fmt_to_planar(format) == format;
}

bool af_fmt_is_spdif(int format)
{
    return af_format_sample_alignment(format) > 1;
}

bool af_fmt_is_pcm(int format)
{
    return af_fmt_is_valid(format) && !af_fmt_is_spdif(format);
}

static const int planar_formats[][2] = {
    {AF_FORMAT_U8P,     AF_FORMAT_U8},
    {AF_FORMAT_S16P,    AF_FORMAT_S16},
    {AF_FORMAT_S32P,    AF_FORMAT_S32},
    {AF_FORMAT_FLOATP,  AF_FORMAT_FLOAT},
    {AF_FORMAT_DOUBLEP, AF_FORMAT_DOUBLE},
};

// Return the planar format corresponding to the given format.
// If the format is already planar, return it.
// Return 0 if there's no equivalent.
int af_fmt_to_planar(int format)
{
    for (int n = 0; n < MP_ARRAY_SIZE(planar_formats); n++) {
        if (planar_formats[n][1] == format)
            return planar_formats[n][0];
        if (planar_formats[n][0] == format)
            return format;
    }
    return 0;
}

// Return the interleaved format corresponding to the given format.
// If the format is already interleaved, return it.
// Always succeeds if format is actually planar; otherwise return 0.
int af_fmt_from_planar(int format)
{
    for (int n = 0; n < MP_ARRAY_SIZE(planar_formats); n++) {
        if (planar_formats[n][0] == format)
            return planar_formats[n][1];
    }
    return format;
}

bool af_fmt_is_valid(int format)
{
    return format > 0 && format < AF_FORMAT_COUNT;
}

const char *af_fmt_to_str(int format)
{
    switch (format) {
    case AF_FORMAT_U8:          return "u8";
    case AF_FORMAT_S16:         return "s16";
    case AF_FORMAT_S32:         return "s32";
    case AF_FORMAT_FLOAT:       return "float";
    case AF_FORMAT_DOUBLE:      return "double";
    case AF_FORMAT_U8P:         return "u8p";
    case AF_FORMAT_S16P:        return "s16p";
    case AF_FORMAT_S32P:        return "s32p";
    case AF_FORMAT_FLOATP:      return "floatp";
    case AF_FORMAT_DOUBLEP:     return "doublep";
    case AF_FORMAT_S_AAC:       return "spdif-aac";
    case AF_FORMAT_S_AC3:       return "spdif-ac3";
    case AF_FORMAT_S_DTS:       return "spdif-dts";
    case AF_FORMAT_S_DTSHD:     return "spdif-dtshd";
    case AF_FORMAT_S_EAC3:      return "spdif-eac3";
    case AF_FORMAT_S_MP3:       return "spdif-mp3";
    case AF_FORMAT_S_TRUEHD:    return "spdif-truehd";
    }
    return "??";
}

int af_fmt_seconds_to_bytes(int format, float seconds, int channels, int samplerate)
{
    assert(!af_fmt_is_planar(format));
    int bps      = af_fmt_to_bytes(format);
    int framelen = channels * bps;
    int bytes    = seconds  * bps * samplerate;
    if (bytes % framelen)
        bytes += framelen - (bytes % framelen);
    return bytes;
}

void af_fill_silence(void *dst, size_t bytes, int format)
{
    memset(dst, af_fmt_is_unsigned(format) ? 0x80 : 0, bytes);
}

// Returns a "score" that serves as heuristic how lossy or hard a conversion is.
// If the formats are equal, 1024 is returned. If they are gravely incompatible
// (like s16<->ac3), INT_MIN is returned. If there is implied loss of precision
// (like s16->s8), a value <0 is returned.
int af_format_conversion_score(int dst_format, int src_format)
{
    if (dst_format == AF_FORMAT_UNKNOWN || src_format == AF_FORMAT_UNKNOWN)
        return INT_MIN;
    if (dst_format == src_format)
        return 1024;
    // Can't be normally converted
    if (!af_fmt_is_pcm(dst_format) || !af_fmt_is_pcm(src_format))
        return INT_MIN;
    int score = 1024;
    if (af_fmt_is_planar(dst_format) != af_fmt_is_planar(src_format))
        score -= 1;     // has to (de-)planarize
    if (af_fmt_is_float(dst_format) != af_fmt_is_float(src_format)) {
        int dst_bytes = af_fmt_to_bytes(dst_format);
        if (af_fmt_is_float(dst_format)) {
            // For int->float, consider a lower bound on the precision difference.
            int bytes = (dst_bytes == 4 ? 3 : 6) - af_fmt_to_bytes(src_format);
            if (bytes >= 0) {
                score -= 8 * bytes;          // excess precision
            } else {
                score += 1024 * (bytes - 1); // precision is lost (i.e. s32 -> float)
            }
        } else {
            // float->int is the worst case. Penalize heavily and
            // prefer highest bit depth int.
            score -= 1048576 * (8 - dst_bytes);
        }
        score -= 512; // penalty for any float <-> int conversion
    } else {
        int bytes = af_fmt_to_bytes(dst_format) - af_fmt_to_bytes(src_format);
        if (bytes > 0) {
            score -= 8 * bytes;          // has to add padding
        } else if (bytes < 0) {
            score += 1024 * (bytes - 1); // has to reduce bit depth
        }
    }
    return score;
}

struct entry {
    int fmt;
    int score;
};

static int cmp_entry(const void *a, const void *b)
{
#define CMP_INT(a, b) (a > b ? 1 : (a < b ? -1 : 0))
    return -CMP_INT(((struct entry *)a)->score, ((struct entry *)b)->score);
}

// Return a list of sample format compatible to src_format, sorted by order
// of preference. out_formats[0] will be src_format (as long as it's valid),
// and the list is terminated with 0 (AF_FORMAT_UNKNOWN).
// Keep in mind that this also returns formats with flipped interleaving
// (e.g. for s16, it returns [s16, s16p, ...]).
// out_formats must be an int[AF_FORMAT_COUNT + 1] array.
void af_get_best_sample_formats(int src_format, int *out_formats)
{
    int num = 0;
    struct entry e[AF_FORMAT_COUNT + 1];
    for (int fmt = 1; fmt < AF_FORMAT_COUNT; fmt++) {
        int score = af_format_conversion_score(fmt, src_format);
        if (score > INT_MIN)
            e[num++] = (struct entry){fmt, score};
    }
    qsort(e, num, sizeof(e[0]), cmp_entry);
    for (int n = 0; n < num; n++)
        out_formats[n] = e[n].fmt;
    out_formats[num] = 0;
}

// Return the best match to src_samplerate from the list provided in the array
// *available, which must be terminated by 0, or itself NULL. If *available is
// empty or NULL, return a negative value. Exact match to src_samplerate is
// most preferred, followed by the lowest integer multiple, followed by the
// maximum of *available.
int af_select_best_samplerate(int src_samplerate, const int *available)
{
    if (!available)
        return -1;

    int min_mult_rate = INT_MAX;
    int max_rate      = INT_MIN;
    for (int i = 0; available[i]; i++) {
        if (available[i] == src_samplerate)
            return available[i];

        if (!(available[i] % src_samplerate))
            min_mult_rate = MPMIN(min_mult_rate, available[i]);

        max_rate = MPMAX(max_rate, available[i]);
    }

    if (min_mult_rate < INT_MAX)
        return min_mult_rate;

    if (max_rate > INT_MIN)
        return max_rate;

    return -1;
}

// Return the number of samples that make up one frame in this format.
// You get the byte size by multiplying them with sample size and channel count.
int af_format_sample_alignment(int format)
{
    switch (format) {
    case AF_FORMAT_S_AAC:       return 16384 / 4;
    case AF_FORMAT_S_AC3:       return 6144 / 4;
    case AF_FORMAT_S_DTSHD:     return 32768 / 16;
    case AF_FORMAT_S_DTS:       return 2048 / 4;
    case AF_FORMAT_S_EAC3:      return 24576 / 4;
    case AF_FORMAT_S_MP3:       return 4608 / 4;
    case AF_FORMAT_S_TRUEHD:    return 61440 / 16;
    default:                    return 1;
    }
}