avcodec: add QOA decoder

Changelog

@@ -5,6 +5,7 @@ version <next>:
 - LEAD MCMP decoder
 - EVC decoding using external library libxevd
 - EVC encoding using external library libxeve
+- QOA decoder
 
 version 6.1:
 - libaribcaption decoder

libavcodec/Makefile

@@ -623,6 +623,7 @@ OBJS-$(CONFIG_QCELP_DECODER)           += qcelpdec.o                     \
 OBJS-$(CONFIG_QDM2_DECODER)            += qdm2.o
 OBJS-$(CONFIG_QDMC_DECODER)            += qdmc.o
 OBJS-$(CONFIG_QDRAW_DECODER)           += qdrw.o
+OBJS-$(CONFIG_QOA_DECODER)             += qoadec.o
 OBJS-$(CONFIG_QOI_DECODER)             += qoidec.o
 OBJS-$(CONFIG_QOI_ENCODER)             += qoienc.o
 OBJS-$(CONFIG_QPEG_DECODER)            += qpeg.o

libavcodec/allcodecs.c

@@ -522,6 +522,7 @@ extern const FFCodec ff_paf_audio_decoder;
 extern const FFCodec ff_qcelp_decoder;
 extern const FFCodec ff_qdm2_decoder;
 extern const FFCodec ff_qdmc_decoder;
+extern const FFCodec ff_qoa_decoder;
 extern const FFCodec ff_ra_144_encoder;
 extern const FFCodec ff_ra_144_decoder;
 extern const FFCodec ff_ra_288_decoder;

libavcodec/codec_desc.c

@@ -3427,6 +3427,13 @@ static const AVCodecDescriptor codec_descriptors[] = {
         .long_name = NULL_IF_CONFIG_SMALL("OSQ (Original Sound Quality)"),
         .props     = AV_CODEC_PROP_INTRA_ONLY | AV_CODEC_PROP_LOSSLESS,
     },
+    {
+        .id        = AV_CODEC_ID_QOA,
+        .type      = AVMEDIA_TYPE_AUDIO,
+        .name      = "qoa",
+        .long_name = NULL_IF_CONFIG_SMALL("QOA (Quite OK Audio)"),
+        .props     = AV_CODEC_PROP_INTRA_ONLY | AV_CODEC_PROP_LOSSY,
+    },
 
     /* subtitle codecs */
     {

libavcodec/codec_id.h

@@ -545,6 +545,7 @@ enum AVCodecID {
     AV_CODEC_ID_RKA,
     AV_CODEC_ID_AC4,
     AV_CODEC_ID_OSQ,
+    AV_CODEC_ID_QOA,
 
     /* subtitle codecs */
     AV_CODEC_ID_FIRST_SUBTITLE = 0x17000,          ///< A dummy ID pointing at the start of subtitle codecs.

libavcodec/qoadec.c

@@ -0,0 +1,175 @@
+/*
+ * QOA decoder
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg 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.
+ *
+ * FFmpeg 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 FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "avcodec.h"
+#include "codec_internal.h"
+#include "decode.h"
+#include "get_bits.h"
+#include "bytestream.h"
+#include "mathops.h"
+
+#define QOA_SLICE_LEN 20
+#define QOA_LMS_LEN 4
+
+typedef struct QOAChannel {
+    int history[QOA_LMS_LEN];
+    int weights[QOA_LMS_LEN];
+} QOAChannel;
+
+typedef struct QOAContext {
+    QOAChannel *ch;
+} QOAContext;
+
+static const int16_t qoa_dequant_tab[16][8] = {
+    {   1,    -1,    3,    -3,    5,    -5,     7,     -7},
+    {   5,    -5,   18,   -18,   32,   -32,    49,    -49},
+    {  16,   -16,   53,   -53,   95,   -95,   147,   -147},
+    {  34,   -34,  113,  -113,  203,  -203,   315,   -315},
+    {  63,   -63,  210,  -210,  378,  -378,   588,   -588},
+    { 104,  -104,  345,  -345,  621,  -621,   966,   -966},
+    { 158,  -158,  528,  -528,  950,  -950,  1477,  -1477},
+    { 228,  -228,  760,  -760, 1368, -1368,  2128,  -2128},
+    { 316,  -316, 1053, -1053, 1895, -1895,  2947,  -2947},
+    { 422,  -422, 1405, -1405, 2529, -2529,  3934,  -3934},
+    { 548,  -548, 1828, -1828, 3290, -3290,  5117,  -5117},
+    { 696,  -696, 2320, -2320, 4176, -4176,  6496,  -6496},
+    { 868,  -868, 2893, -2893, 5207, -5207,  8099,  -8099},
+    {1064, -1064, 3548, -3548, 6386, -6386,  9933,  -9933},
+    {1286, -1286, 4288, -4288, 7718, -7718, 12005, -12005},
+    {1536, -1536, 5120, -5120, 9216, -9216, 14336, -14336},
+};
+
+static av_cold int qoa_decode_init(AVCodecContext *avctx)
+{
+    QOAContext *s = avctx->priv_data;
+
+    avctx->sample_fmt = AV_SAMPLE_FMT_S16;
+
+    s->ch = av_calloc(avctx->ch_layout.nb_channels, sizeof(*s->ch));
+    if (!s->ch)
+        return AVERROR(ENOMEM);
+
+    return 0;
+}
+
+static int qoa_lms_predict(QOAChannel *lms)
+{
+    int prediction = 0;
+    for (int i = 0; i < QOA_LMS_LEN; i++)
+        prediction += lms->weights[i] * lms->history[i];
+    return prediction >> 13;
+}
+
+static void qoa_lms_update(QOAChannel *lms, int sample, int residual)
+{
+    int delta = residual >> 4;
+    for (int i = 0; i < QOA_LMS_LEN; i++)
+        lms->weights[i] += lms->history[i] < 0 ? -delta : delta;
+    for (int i = 0; i < QOA_LMS_LEN-1; i++)
+        lms->history[i] = lms->history[i+1];
+    lms->history[QOA_LMS_LEN-1] = sample;
+}
+
+static int qoa_decode_frame(AVCodecContext *avctx, AVFrame *frame,
+                            int *got_frame_ptr, AVPacket *avpkt)
+{
+    QOAContext *s = avctx->priv_data;
+    int ret, frame_size, nb_channels;
+    GetByteContext gb;
+    int16_t *samples;
+
+    bytestream2_init(&gb, avpkt->data, avpkt->size);
+
+    nb_channels = bytestream2_get_byte(&gb);
+    if (avctx->ch_layout.nb_channels != nb_channels)
+        return AVERROR_INVALIDDATA;
+
+    avctx->sample_rate = bytestream2_get_be24(&gb);
+    frame->nb_samples = bytestream2_get_be16(&gb);
+    frame_size = bytestream2_get_be16(&gb);
+    if (frame_size > avpkt->size)
+        return AVERROR_INVALIDDATA;
+
+    if (frame_size < 8 + QOA_LMS_LEN * 4 * nb_channels +
+        8LL * frame->nb_samples * nb_channels / QOA_SLICE_LEN)
+        return AVERROR_INVALIDDATA;
+
+    if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
+        return ret;
+    samples = (int16_t *)frame->data[0];
+
+    for (int ch = 0; ch < nb_channels; ch++) {
+        QOAChannel *qch = &s->ch[ch];
+
+        for (int n = 0; n < QOA_LMS_LEN; n++)
+            qch->history[n] = sign_extend(bytestream2_get_be16u(&gb), 16);
+        for (int n = 0; n < QOA_LMS_LEN; n++)
+            qch->weights[n] = sign_extend(bytestream2_get_be16u(&gb), 16);
+    }
+
+    for (int sample_index = 0; sample_index < frame->nb_samples * nb_channels;
+         sample_index += QOA_SLICE_LEN) {
+        for (int ch = 0; ch < nb_channels; ch++) {
+            QOAChannel *lms = &s->ch[ch];
+            uint64_t slice = bytestream2_get_be64u(&gb);
+            int scalefactor = (slice >> 60) & 0xf;
+            int slice_start = sample_index * nb_channels + ch;
+            int slice_end = av_clip(sample_index + QOA_SLICE_LEN, 0, frame->nb_samples) * nb_channels + ch;
+
+            for (int si = slice_start; si < slice_end; si += nb_channels) {
+                int predicted = qoa_lms_predict(lms);
+                int quantized = (slice >> 57) & 0x7;
+                int dequantized = qoa_dequant_tab[scalefactor][quantized];
+                int reconstructed = av_clip_int16(predicted + dequantized);
+
+                samples[si] = reconstructed;
+                slice <<= 3;
+
+                qoa_lms_update(lms, reconstructed, dequantized);
+            }
+        }
+    }
+
+    *got_frame_ptr = 1;
+
+    return avpkt->size;
+}
+
+static av_cold int qoa_decode_end(AVCodecContext *avctx)
+{
+    QOAContext *s = avctx->priv_data;
+    av_freep(&s->ch);
+    return 0;
+}
+
+const FFCodec ff_qoa_decoder = {
+    .p.name         = "qoa",
+    CODEC_LONG_NAME("QOA (Quite OK Audio)"),
+    .p.type         = AVMEDIA_TYPE_AUDIO,
+    .p.id           = AV_CODEC_ID_QOA,
+    .priv_data_size = sizeof(QOAContext),
+    .init           = qoa_decode_init,
+    FF_CODEC_DECODE_CB(qoa_decode_frame),
+    .close          = qoa_decode_end,
+    .p.capabilities = AV_CODEC_CAP_CHANNEL_CONF |
+                      AV_CODEC_CAP_DR1,
+    .p.sample_fmts  = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S16,
+                                                      AV_SAMPLE_FMT_NONE },
+};

libavcodec/version.h

@@ -29,7 +29,7 @@
 
 #include "version_major.h"
 
-#define LIBAVCODEC_VERSION_MINOR  34
+#define LIBAVCODEC_VERSION_MINOR  35
 #define LIBAVCODEC_VERSION_MICRO 100
 
 #define LIBAVCODEC_VERSION_INT  AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \