mpv/audio/format.c

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/*
* Copyright (C) 2005 Alex Beregszaszi
*
* This file is part of MPlayer.
*
* MPlayer is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* MPlayer 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with MPlayer; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <inttypes.h>
#include <limits.h>
#include <assert.h>
#include "common/common.h"
#include "audio/filter/af.h"
int af_fmt2bits(int format)
{
if (AF_FORMAT_IS_AC3(format)) return 16;
if (format == AF_FORMAT_UNKNOWN)
return 0;
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switch (format & AF_FORMAT_BITS_MASK) {
case AF_FORMAT_8BIT: return 8;
case AF_FORMAT_16BIT: return 16;
case AF_FORMAT_24BIT: return 24;
case AF_FORMAT_32BIT: return 32;
case AF_FORMAT_64BIT: return 64;
}
return 0;
}
static int bits_to_mask(int bits)
{
switch (bits) {
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case 8: return AF_FORMAT_8BIT;
case 16: return AF_FORMAT_16BIT;
case 24: return AF_FORMAT_24BIT;
case 32: return AF_FORMAT_32BIT;
case 64: return AF_FORMAT_64BIT;
}
return 0;
}
int af_fmt_change_bits(int format, int bits)
{
if (!af_fmt_is_valid(format) || (format & AF_FORMAT_SPECIAL_MASK))
return 0;
int mask = bits_to_mask(bits);
format = (format & ~AF_FORMAT_BITS_MASK) | mask;
return af_fmt_is_valid(format) ? format : 0;
}
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;
}
// false for interleaved and AF_FORMAT_UNKNOWN
bool af_fmt_is_planar(int format)
{
return !!(format & AF_FORMAT_PLANAR);
}
#define FMT(string, id) \
{string, id},
#define FMT_ENDIAN(string, id) \
{string, id}, \
{string "le", MP_CONCAT(id, _LE)}, \
{string "be", MP_CONCAT(id, _BE)}, \
const struct af_fmt_entry af_fmtstr_table[] = {
FMT("mpeg2", AF_FORMAT_MPEG2)
FMT_ENDIAN("ac3", AF_FORMAT_AC3)
FMT_ENDIAN("iec61937", AF_FORMAT_IEC61937)
FMT("u8", AF_FORMAT_U8)
FMT("s8", AF_FORMAT_S8)
FMT_ENDIAN("u16", AF_FORMAT_U16)
FMT_ENDIAN("s16", AF_FORMAT_S16)
FMT_ENDIAN("u24", AF_FORMAT_U24)
FMT_ENDIAN("s24", AF_FORMAT_S24)
FMT_ENDIAN("u32", AF_FORMAT_U32)
FMT_ENDIAN("s32", AF_FORMAT_S32)
FMT_ENDIAN("float", AF_FORMAT_FLOAT)
FMT_ENDIAN("double", AF_FORMAT_DOUBLE)
FMT("u8p", AF_FORMAT_U8P)
FMT("s16p", AF_FORMAT_S16P)
FMT("s32p", AF_FORMAT_S32P)
FMT("floatp", AF_FORMAT_FLOATP)
FMT("doublep", AF_FORMAT_DOUBLEP)
{0}
};
bool af_fmt_is_valid(int format)
{
for (int i = 0; af_fmtstr_table[i].name; i++) {
if (af_fmtstr_table[i].format == format)
return true;
}
return false;
}
const char *af_fmt_to_str(int format)
{
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for (int i = 0; af_fmtstr_table[i].name; i++) {
if (af_fmtstr_table[i].format == format)
return af_fmtstr_table[i].name;
}
return "??";
}
int af_fmt_seconds_to_bytes(int format, float seconds, int channels, int samplerate)
{
assert(!af_fmt_is_planar(format));
int bps = (af_fmt2bits(format) / 8);
int framelen = channels * bps;
int bytes = seconds * bps * samplerate;
if (bytes % framelen)
bytes += framelen - (bytes % framelen);
return bytes;
}
int af_str2fmt_short(bstr str)
{
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for (int i = 0; af_fmtstr_table[i].name; i++) {
if (!bstrcasecmp0(str, af_fmtstr_table[i].name))
return af_fmtstr_table[i].format;
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}
return 0;
}
void af_fill_silence(void *dst, size_t bytes, int format)
{
bool us = (format & AF_FORMAT_SIGN_MASK) == AF_FORMAT_US;
memset(dst, us ? 0x80 : 0, bytes);
}
audio/format: add heuristic to estimate loss on format conversion The added function af_format_conversion_score() can be used to select the best sample format to convert to in order to reduce loss and extra conversion work. It calculates a "loss" score when going from one format to another, and for each conversion that needs to be done a certain score is subtracted. Thus, if you have to convert from one format to a set of other formats, you can calculate the score for each conversion, and pick the one with the highest score. Conversion between int and float is considered the worst case. One odd consequence is that when converting from s32 to u8 or float, u8 will be picked. Test program used to develop this follows: #define MAX_FMT 200 struct entry { const char *name; int score; }; static int compentry(const void *px1, const void *px2) { const struct entry *x1 = px1; const struct entry *x2 = px2; if (x1->score > x2->score) return 1; if (x1->score < x2->score) return -1; return 0; } int main(int argc, char *argv[]) { for (int n = 0; af_fmtstr_table[n].name; n++) { struct entry entry[MAX_FMT]; int entries = 0; for (int i = 0; af_fmtstr_table[i].name; i++) { assert(i < MAX_FMT); entry[entries].name = af_fmtstr_table[i].name; entry[entries].score = af_format_conversion_score(af_fmtstr_table[i].format, af_fmtstr_table[n].format); entries++; } qsort(&entry[0], entries, sizeof(entry[0]), compentry); for (int i = 0; i < entries; i++) { printf("%s -> %s: %d \n", af_fmtstr_table[n].name, entry[i].name, entry[i].score); } } }
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#define FMT_DIFF(type, a, b) (((a) & type) - ((b) & type))
// 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;
// Just endian swapping (separate because it works for special formats)
if ((dst_format & ~AF_FORMAT_END_MASK) == (src_format & ~AF_FORMAT_END_MASK))
return 1024 - 2;
// Can't be normally converted
if (AF_FORMAT_IS_SPECIAL(dst_format) || AF_FORMAT_IS_SPECIAL(src_format))
return INT_MIN;
int score = 1024;
if (FMT_DIFF(AF_FORMAT_INTERLEAVING_MASK, dst_format, src_format))
score -= 1; // has to (de-)planarize
if (FMT_DIFF(AF_FORMAT_END_MASK, dst_format, src_format))
score -= 2; // has to swap endian
if (FMT_DIFF(AF_FORMAT_SIGN_MASK, dst_format, src_format))
score -= 4; // has to swap sign
if (FMT_DIFF(AF_FORMAT_POINT_MASK, dst_format, src_format)) {
int dst_bits = dst_format & AF_FORMAT_BITS_MASK;
if ((dst_format & AF_FORMAT_POINT_MASK) == AF_FORMAT_F) {
// For int->float, always prefer 32 bit float.
score -= dst_bits == AF_FORMAT_32BIT ? 8 : 0;
} else {
// For float->int, always prefer highest bit depth int
score -= 8 * (AF_FORMAT_64BIT - dst_bits);
}
} else {
int bits = FMT_DIFF(AF_FORMAT_BITS_MASK, dst_format, src_format);
if (bits > 0) {
score -= 8 * bits; // has to add padding
} else if (bits < 0) {
score -= 1024 - 8 * bits; // has to reduce bit depth
}
}
// Consider this the worst case.
if (FMT_DIFF(AF_FORMAT_POINT_MASK, dst_format, src_format))
score -= 2048; // has to convert float<->int
return score;
}