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https://github.com/mpv-player/mpv
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279f4b59dc
The libavresample version of the current Libav stable release lacks the
avresample_set_channel_mapping() function. (FFmpeg's libswresample seems
to be fine, because they added swr_set_channel_mapping() first.)
Add a cheap/slow workaround to do channel reordering on our own. We
don't use the recently removed MPlayer code (see commit 586b75a
),
because that is not generic enough.
The functionality should be the same as with full-featured
libavresample, and any differences are bugs. It's probably slower,
though.
146 lines
5.2 KiB
C
146 lines
5.2 KiB
C
/*
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* common functions for reordering audio channels
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*
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* Copyright (C) 2007 Ulion <ulion A gmail P com>
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*
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* This file is part of MPlayer.
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*
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* MPlayer is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* MPlayer is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with MPlayer; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#include <inttypes.h>
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#include <string.h>
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#include <assert.h>
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#include "chmap.h"
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#include "reorder_ch.h"
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static inline void reorder_to_planar_(void *restrict out, const void *restrict in,
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size_t size, size_t nchan, size_t nmemb)
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{
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size_t i, c;
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char *outptr = (char *) out;
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size_t instep = nchan * size;
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for (c = 0; c < nchan; ++c) {
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const char *inptr = ((const char *) in) + c * size;
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for (i = 0; i < nmemb; ++i, inptr += instep, outptr += size) {
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memcpy(outptr, inptr, size);
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}
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}
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}
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void reorder_to_planar(void *restrict out, const void *restrict in,
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size_t size, size_t nchan, size_t nmemb)
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{
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// special case for mono (nothing to do...)
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if (nchan == 1)
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memcpy(out, in, size * nchan * nmemb);
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// these calls exist to insert an inline copy of to_planar_ here with known
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// value of size to help the compiler replace the memcpy calls by mov
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// instructions
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else if (size == 1)
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reorder_to_planar_(out, in, 1, nchan, nmemb);
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else if (size == 2)
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reorder_to_planar_(out, in, 2, nchan, nmemb);
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else if (size == 4)
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reorder_to_planar_(out, in, 4, nchan, nmemb);
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// general case (calls memcpy a lot, should actually never happen, but
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// stays here for correctness purposes)
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else
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reorder_to_planar_(out, in, size, nchan, nmemb);
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}
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static inline void reorder_to_packed_(uint8_t *out, uint8_t **in,
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size_t size, size_t nchan, size_t nmemb)
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{
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size_t outstep = nchan * size;
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for (size_t c = 0; c < nchan; ++c) {
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char *outptr = out + c * size;
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char *inptr = in[c];
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for (size_t i = 0; i < nmemb; ++i, outptr += outstep, inptr += size) {
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memcpy(outptr, inptr, size);
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}
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}
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}
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// out = destination array of packed samples of given size, nmemb frames
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// in[channel] = source array of samples for the given channel
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void reorder_to_packed(uint8_t *out, uint8_t **in,
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size_t size, size_t nchan, size_t nmemb)
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{
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if (nchan == 1)
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memcpy(out, in, size * nchan * nmemb);
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// See reorder_to_planar() why this is done this way
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else if (size == 1)
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reorder_to_packed_(out, in, 1, nchan, nmemb);
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else if (size == 2)
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reorder_to_packed_(out, in, 2, nchan, nmemb);
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else if (size == 4)
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reorder_to_packed_(out, in, 4, nchan, nmemb);
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else
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reorder_to_packed_(out, in, size, nchan, nmemb);
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}
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#define MAX_SAMPLESIZE 8
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static void reorder_channels_(uint8_t *restrict data, int *restrict ch_order,
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size_t sample_size, size_t num_ch,
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size_t num_frames)
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{
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char buffer[MP_NUM_CHANNELS * MAX_SAMPLESIZE];
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for (size_t f = 0; f < num_frames; f++) {
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for (uint8_t c = 0; c < num_ch; c++) {
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memcpy(buffer + sample_size * c, data + sample_size * ch_order[c],
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sample_size);
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}
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memcpy(data, buffer, sample_size * num_ch);
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data += num_ch * sample_size;
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}
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}
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// Reorders for each channel:
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// out[ch] = in[ch_order[ch]] (but in-place)
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// num_ch is the number of channels
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// sample_size is e.g. 2 for s16le
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// full byte size of in/out = num_ch * sample_size * num_frames
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// Do not use this function in new code; use libavresample instead.
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void reorder_channels(void *restrict data, int *restrict ch_order,
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size_t sample_size, size_t num_ch, size_t num_frames)
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{
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// Check 1:1 mapping
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bool need_reorder = false;
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for (int n = 0; n < num_ch; n++)
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need_reorder |= ch_order[n] != n;
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if (!need_reorder)
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return;
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assert(sample_size <= MAX_SAMPLESIZE);
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assert(num_ch <= MP_NUM_CHANNELS);
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// See reorder_to_planar() why this is done this way
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// s16 and float are the most common sample sizes, and 6 channels is the
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// most common case where reordering is required.
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if (sample_size == 2 && num_ch == 6)
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reorder_channels_(data, ch_order, 2, 6, num_frames);
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else if (sample_size == 2)
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reorder_channels_(data, ch_order, 2, num_ch, num_frames);
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else if (sample_size == 4 && num_ch == 6)
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reorder_channels_(data, ch_order, 4, 6, num_frames);
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else if (sample_size == 4)
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reorder_channels_(data, ch_order, 4, num_ch, num_frames);
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else
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reorder_channels_(data, ch_order, sample_size, num_ch, num_frames);
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}
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