mirror of https://github.com/FFmpeg/FFmpeg.git
Paul B Mahol
1 year ago
parent
93b5d9030b
commit
3609d2b783
7 changed files with 187 additions and 1 deletions
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/*
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* QOA decoder |
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* |
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* This file is part of FFmpeg. |
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* |
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* FFmpeg is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public |
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* License as published by the Free Software Foundation; either |
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* version 2.1 of the License, or (at your option) any later version. |
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* |
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* FFmpeg 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 GNU |
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* Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public |
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* License along with FFmpeg; if not, write to the Free Software |
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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*/ |
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#include "avcodec.h" |
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#include "codec_internal.h" |
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#include "decode.h" |
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#include "get_bits.h" |
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#include "bytestream.h" |
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#include "mathops.h" |
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#define QOA_SLICE_LEN 20 |
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#define QOA_LMS_LEN 4 |
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typedef struct QOAChannel { |
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int history[QOA_LMS_LEN]; |
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int weights[QOA_LMS_LEN]; |
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} QOAChannel; |
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typedef struct QOAContext { |
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QOAChannel *ch; |
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} QOAContext; |
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static const int16_t qoa_dequant_tab[16][8] = { |
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{ 1, -1, 3, -3, 5, -5, 7, -7}, |
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{ 5, -5, 18, -18, 32, -32, 49, -49}, |
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{ 16, -16, 53, -53, 95, -95, 147, -147}, |
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{ 34, -34, 113, -113, 203, -203, 315, -315}, |
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{ 63, -63, 210, -210, 378, -378, 588, -588}, |
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{ 104, -104, 345, -345, 621, -621, 966, -966}, |
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{ 158, -158, 528, -528, 950, -950, 1477, -1477}, |
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{ 228, -228, 760, -760, 1368, -1368, 2128, -2128}, |
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{ 316, -316, 1053, -1053, 1895, -1895, 2947, -2947}, |
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{ 422, -422, 1405, -1405, 2529, -2529, 3934, -3934}, |
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{ 548, -548, 1828, -1828, 3290, -3290, 5117, -5117}, |
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{ 696, -696, 2320, -2320, 4176, -4176, 6496, -6496}, |
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{ 868, -868, 2893, -2893, 5207, -5207, 8099, -8099}, |
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{1064, -1064, 3548, -3548, 6386, -6386, 9933, -9933}, |
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{1286, -1286, 4288, -4288, 7718, -7718, 12005, -12005}, |
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{1536, -1536, 5120, -5120, 9216, -9216, 14336, -14336}, |
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}; |
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static av_cold int qoa_decode_init(AVCodecContext *avctx) |
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{ |
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QOAContext *s = avctx->priv_data; |
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avctx->sample_fmt = AV_SAMPLE_FMT_S16; |
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s->ch = av_calloc(avctx->ch_layout.nb_channels, sizeof(*s->ch)); |
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if (!s->ch) |
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return AVERROR(ENOMEM); |
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return 0; |
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} |
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static int qoa_lms_predict(QOAChannel *lms) |
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{ |
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int prediction = 0; |
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for (int i = 0; i < QOA_LMS_LEN; i++) |
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prediction += lms->weights[i] * lms->history[i]; |
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return prediction >> 13; |
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} |
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static void qoa_lms_update(QOAChannel *lms, int sample, int residual) |
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{ |
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int delta = residual >> 4; |
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for (int i = 0; i < QOA_LMS_LEN; i++) |
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lms->weights[i] += lms->history[i] < 0 ? -delta : delta; |
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for (int i = 0; i < QOA_LMS_LEN-1; i++) |
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lms->history[i] = lms->history[i+1]; |
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lms->history[QOA_LMS_LEN-1] = sample; |
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} |
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static int qoa_decode_frame(AVCodecContext *avctx, AVFrame *frame, |
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int *got_frame_ptr, AVPacket *avpkt) |
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{ |
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QOAContext *s = avctx->priv_data; |
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int ret, frame_size, nb_channels; |
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GetByteContext gb; |
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int16_t *samples; |
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bytestream2_init(&gb, avpkt->data, avpkt->size); |
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nb_channels = bytestream2_get_byte(&gb); |
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if (avctx->ch_layout.nb_channels != nb_channels) |
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return AVERROR_INVALIDDATA; |
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avctx->sample_rate = bytestream2_get_be24(&gb); |
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frame->nb_samples = bytestream2_get_be16(&gb); |
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frame_size = bytestream2_get_be16(&gb); |
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if (frame_size > avpkt->size) |
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return AVERROR_INVALIDDATA; |
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if (frame_size < 8 + QOA_LMS_LEN * 4 * nb_channels + |
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8LL * frame->nb_samples * nb_channels / QOA_SLICE_LEN) |
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return AVERROR_INVALIDDATA; |
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if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) |
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return ret; |
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samples = (int16_t *)frame->data[0]; |
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for (int ch = 0; ch < nb_channels; ch++) { |
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QOAChannel *qch = &s->ch[ch]; |
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for (int n = 0; n < QOA_LMS_LEN; n++) |
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qch->history[n] = sign_extend(bytestream2_get_be16u(&gb), 16); |
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for (int n = 0; n < QOA_LMS_LEN; n++) |
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qch->weights[n] = sign_extend(bytestream2_get_be16u(&gb), 16); |
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} |
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for (int sample_index = 0; sample_index < frame->nb_samples * nb_channels; |
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sample_index += QOA_SLICE_LEN) { |
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for (int ch = 0; ch < nb_channels; ch++) { |
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QOAChannel *lms = &s->ch[ch]; |
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uint64_t slice = bytestream2_get_be64u(&gb); |
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int scalefactor = (slice >> 60) & 0xf; |
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int slice_start = sample_index * nb_channels + ch; |
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int slice_end = av_clip(sample_index + QOA_SLICE_LEN, 0, frame->nb_samples) * nb_channels + ch; |
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for (int si = slice_start; si < slice_end; si += nb_channels) { |
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int predicted = qoa_lms_predict(lms); |
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int quantized = (slice >> 57) & 0x7; |
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int dequantized = qoa_dequant_tab[scalefactor][quantized]; |
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int reconstructed = av_clip_int16(predicted + dequantized); |
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samples[si] = reconstructed; |
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slice <<= 3; |
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qoa_lms_update(lms, reconstructed, dequantized); |
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} |
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} |
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} |
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*got_frame_ptr = 1; |
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return avpkt->size; |
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} |
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static av_cold int qoa_decode_end(AVCodecContext *avctx) |
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{ |
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QOAContext *s = avctx->priv_data; |
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av_freep(&s->ch); |
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return 0; |
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} |
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const FFCodec ff_qoa_decoder = { |
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.p.name = "qoa", |
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CODEC_LONG_NAME("QOA (Quite OK Audio)"), |
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.p.type = AVMEDIA_TYPE_AUDIO, |
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.p.id = AV_CODEC_ID_QOA, |
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.priv_data_size = sizeof(QOAContext), |
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.init = qoa_decode_init, |
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FF_CODEC_DECODE_CB(qoa_decode_frame), |
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.close = qoa_decode_end, |
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.p.capabilities = AV_CODEC_CAP_CHANNEL_CONF | |
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AV_CODEC_CAP_DR1, |
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.p.sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S16, |
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AV_SAMPLE_FMT_NONE }, |
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}; |
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