tta encoder

Signed-off-by: Paul B Mahol <onemda@gmail.com>

1 files changed, 232 insertions, 0 deletions

diff --git a/libavcodec/ttaenc.c b/libavcodec/ttaenc.c
new file mode 100644
index 0000000000..c77e0c29b0
--- /dev/null
+++ b/libavcodec/ttaenc.c
@@ -0,0 +1,232 @@
+/*
+ * TTA (The Lossless True Audio) encoder
+ *
+ * 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
+ */
+
+#define BITSTREAM_WRITER_LE
+#include "ttadata.h"
+#include "avcodec.h"
+#include "put_bits.h"
+#include "internal.h"
+#include "libavutil/crc.h"
+
+typedef struct TTAEncContext {
+    const AVCRC *crc_table;
+    int bps;
+    TTAChannel *ch_ctx;
+} TTAEncContext;
+
+static av_cold int tta_encode_init(AVCodecContext *avctx)
+{
+    TTAEncContext *s = avctx->priv_data;
+
+    s->crc_table = av_crc_get_table(AV_CRC_32_IEEE_LE);
+
+    switch (avctx->sample_fmt) {
+    case AV_SAMPLE_FMT_U8:
+        avctx->bits_per_raw_sample = 8;
+        break;
+    case AV_SAMPLE_FMT_S16:
+        avctx->bits_per_raw_sample = 16;
+        break;
+    case AV_SAMPLE_FMT_S32:
+        if (avctx->bits_per_raw_sample > 24)
+            av_log(avctx, AV_LOG_WARNING, "encoding as 24 bits-per-sample\n");
+        avctx->bits_per_raw_sample = 24;
+    }
+
+    s->bps = avctx->bits_per_raw_sample >> 3;
+    avctx->frame_size = 256 * avctx->sample_rate / 245;
+
+    s->ch_ctx = av_malloc(avctx->channels * sizeof(*s->ch_ctx));
+    if (!s->ch_ctx)
+        return AVERROR(ENOMEM);
+
+    return 0;
+}
+
+static inline void ttafilter_process(TTAFilter *c, int32_t *in)
+{
+    register int32_t *dl = c->dl, *qm = c->qm, *dx = c->dx, sum = c->round;
+
+    if (c->error < 0) {
+        qm[0] -= dx[0]; qm[1] -= dx[1]; qm[2] -= dx[2]; qm[3] -= dx[3];
+        qm[4] -= dx[4]; qm[5] -= dx[5]; qm[6] -= dx[6]; qm[7] -= dx[7];
+    } else if (c->error > 0) {
+        qm[0] += dx[0]; qm[1] += dx[1]; qm[2] += dx[2]; qm[3] += dx[3];
+        qm[4] += dx[4]; qm[5] += dx[5]; qm[6] += dx[6]; qm[7] += dx[7];
+    }
+
+    sum += dl[0] * qm[0] + dl[1] * qm[1] + dl[2] * qm[2] + dl[3] * qm[3] +
+           dl[4] * qm[4] + dl[5] * qm[5] + dl[6] * qm[6] + dl[7] * qm[7];
+
+    dx[0] = dx[1]; dx[1] = dx[2]; dx[2] = dx[3]; dx[3] = dx[4];
+    dl[0] = dl[1]; dl[1] = dl[2]; dl[2] = dl[3]; dl[3] = dl[4];
+
+    dx[4] = ((dl[4] >> 30) | 1);
+    dx[5] = ((dl[5] >> 30) | 2) & ~1;
+    dx[6] = ((dl[6] >> 30) | 2) & ~1;
+    dx[7] = ((dl[7] >> 30) | 4) & ~3;
+
+    dl[4] = -dl[5]; dl[5] = -dl[6];
+    dl[6] = *in - dl[7]; dl[7] = *in;
+    dl[5] += dl[6]; dl[4] += dl[5];
+
+    *in -= (sum >> c->shift);
+    c->error = *in;
+}
+
+static int32_t get_sample(const AVFrame *frame, int sample,
+                          enum AVSampleFormat format)
+{
+    int32_t ret;
+
+    if (format == AV_SAMPLE_FMT_U8) {
+        ret = frame->data[0][sample] - 0x80;
+    } else if (format == AV_SAMPLE_FMT_S16) {
+        const int16_t *ptr = (const int16_t *)frame->data[0];
+        ret = ptr[sample];
+    } else {
+        const int32_t *ptr = (const int32_t *)frame->data[0];
+        ret = ptr[sample] >> 8;
+    }
+
+    return ret;
+}
+
+static int tta_encode_frame(AVCodecContext *avctx, AVPacket *avpkt,
+                            const AVFrame *frame, int *got_packet_ptr)
+{
+    TTAEncContext *s = avctx->priv_data;
+    PutBitContext pb;
+    int ret, i, out_bytes, cur_chan = 0, res = 0, samples = 0;
+
+    if ((ret = ff_alloc_packet2(avctx, avpkt, frame->nb_samples * 2 * s->bps)) < 0)
+        return ret;
+    init_put_bits(&pb, avpkt->data, avpkt->size);
+
+    // init per channel states
+    for (i = 0; i < avctx->channels; i++) {
+        s->ch_ctx[i].predictor = 0;
+        ff_tta_filter_init(&s->ch_ctx[i].filter, ff_tta_filter_configs[s->bps - 1]);
+        ff_tta_rice_init(&s->ch_ctx[i].rice, 10, 10);
+    }
+
+    for (i = 0; i < frame->nb_samples * avctx->channels; i++) {
+        TTAChannel *c = &s->ch_ctx[cur_chan];
+        TTAFilter *filter = &c->filter;
+        TTARice *rice = &c->rice;
+        uint32_t k, unary, outval;
+        int32_t value, temp;
+
+        value = get_sample(frame, samples++, avctx->sample_fmt);
+
+        if (avctx->channels > 1) {
+            if (cur_chan < avctx->channels - 1)
+                value  = res = get_sample(frame, samples, avctx->sample_fmt) - value;
+            else
+                value -= res / 2;
+        }
+
+        temp = value;
+#define PRED(x, k) (int32_t)((((uint64_t)x << k) - x) >> k)
+        switch (s->bps) {
+        case 1: value -= PRED(c->predictor, 4); break;
+        case 2:
+        case 3: value -= PRED(c->predictor, 5); break;
+        }
+        c->predictor = temp;
+
+        ttafilter_process(filter, &value);
+        outval = (value > 0) ? (value << 1) - 1: -value << 1;
+
+        k = rice->k0;
+
+        rice->sum0 += outval - (rice->sum0 >> 4);
+        if (rice->k0 > 0 && rice->sum0 < ff_tta_shift_16[rice->k0])
+            rice->k0--;
+        else if (rice->sum0 > ff_tta_shift_16[rice->k0 + 1])
+            rice->k0++;
+
+        if (outval >= ff_tta_shift_1[k]) {
+            outval -= ff_tta_shift_1[k];
+            k = rice->k1;
+
+            rice->sum1 += outval - (rice->sum1 >> 4);
+            if (rice->k1 > 0 && rice->sum1 < ff_tta_shift_16[rice->k1])
+                rice->k1--;
+            else if (rice->sum1 > ff_tta_shift_16[rice->k1 + 1])
+                rice->k1++;
+
+            unary = 1 + (outval >> k);
+            do {
+                if (unary > 31) {
+                    put_bits(&pb, 31, 0x7FFFFFFF);
+                    unary -= 31;
+                } else {
+                    put_bits(&pb, unary, (1 << unary) - 1);
+                    unary = 0;
+                }
+            } while (unary);
+        }
+
+        put_bits(&pb, 1, 0);
+
+        if (k)
+            put_bits(&pb, k, outval & (ff_tta_shift_1[k] - 1));
+
+        if (cur_chan < avctx->channels - 1)
+            cur_chan++;
+        else
+            cur_chan = 0;
+    }
+
+    flush_put_bits(&pb);
+    out_bytes = put_bits_count(&pb) >> 3;
+    put_bits32(&pb, av_crc(s->crc_table, UINT32_MAX, avpkt->data, out_bytes) ^ UINT32_MAX);
+    flush_put_bits(&pb);
+
+    avpkt->pts      = frame->pts;
+    avpkt->size     = out_bytes + 4;
+    avpkt->duration = ff_samples_to_time_base(avctx, frame->nb_samples);
+    *got_packet_ptr = 1;
+    return 0;
+}
+
+static av_cold int tta_encode_close(AVCodecContext *avctx)
+{
+    TTAEncContext *s = avctx->priv_data;
+    av_freep(&s->ch_ctx);
+    return 0;
+}
+
+AVCodec ff_tta_encoder = {
+    .name           = "tta",
+    .type           = AVMEDIA_TYPE_AUDIO,
+    .id             = AV_CODEC_ID_TTA,
+    .priv_data_size = sizeof(TTAEncContext),
+    .init           = tta_encode_init,
+    .close          = tta_encode_close,
+    .encode2        = tta_encode_frame,
+    .capabilities   = CODEC_CAP_SMALL_LAST_FRAME | CODEC_CAP_LOSSLESS,
+    .sample_fmts    = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_U8,
+                                                     AV_SAMPLE_FMT_S16,
+                                                     AV_SAMPLE_FMT_S32,
+                                                     AV_SAMPLE_FMT_NONE },
+    .long_name      = NULL_IF_CONFIG_SMALL("TTA (True Audio)"),
+};