s302m encoder

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

1 files changed, 176 insertions, 0 deletions

diff --git a/libavcodec/s302menc.c b/libavcodec/s302menc.c
new file mode 100644
index 0000000000..325c1ed634
--- /dev/null
+++ b/libavcodec/s302menc.c
@@ -0,0 +1,176 @@
+/*
+ * SMPTE 302M encoder
+ * Copyright (c) 2010 Google, Inc.
+ * Copyright (c) 2013 Darryl Wallace <wallacdj@gmail.com>
+ *
+ * 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 "internal.h"
+#include "put_bits.h"
+
+#define AES3_HEADER_LEN 4
+
+typedef struct S302MEncContext {
+    uint8_t framing_index; /* Set for even channels on multiple of 192 samples */
+} S302MEncContext;
+
+static av_cold int s302m_encode_init(AVCodecContext *avctx)
+{
+    S302MEncContext *s = avctx->priv_data;
+
+    if (avctx->channels & 1 || avctx->channels > 8) {
+        av_log(avctx, AV_LOG_ERROR,
+               "Encoding %d channel(s) is not allowed. Only 2, 4, 6 and 8 channels are supported.\n",
+               avctx->channels);
+        return AVERROR(EINVAL);
+    }
+
+    switch (avctx->sample_fmt) {
+    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;
+        } else if (!avctx->bits_per_raw_sample) {
+            avctx->bits_per_raw_sample = 24;
+        } else if (avctx->bits_per_raw_sample <= 20) {
+            avctx->bits_per_raw_sample = 20;
+        }
+    }
+
+    avctx->frame_size = 0;
+    avctx->bit_rate   = 48000 * avctx->channels *
+                       (avctx->bits_per_raw_sample + 4);
+    s->framing_index  = 0;
+
+    return 0;
+}
+
+static int s302m_encode2_frame(AVCodecContext *avctx, AVPacket *avpkt,
+                               const AVFrame *frame, int *got_packet_ptr)
+{
+    S302MEncContext *s = avctx->priv_data;
+    const int buf_size = AES3_HEADER_LEN +
+                        (frame->nb_samples *
+                         avctx->channels *
+                        (avctx->bits_per_raw_sample + 4)) / 8;
+    int ret, c, channels;
+    uint8_t *o;
+    PutBitContext pb;
+
+    if ((ret = ff_alloc_packet2(avctx, avpkt, buf_size)) < 0)
+        return ret;
+
+    o = avpkt->data;
+    init_put_bits(&pb, o, buf_size * 8);
+    put_bits(&pb, 16, buf_size - AES3_HEADER_LEN);
+    put_bits(&pb, 2, (avctx->channels - 2) >> 1);   // number of channels
+    put_bits(&pb, 8, 0);                            // channel ID
+    put_bits(&pb, 2, (avctx->bits_per_raw_sample - 16) / 4); // bits per samples (0 = 16bit, 1 = 20bit, 2 = 24bit)
+    put_bits(&pb, 4, 0);                            // alignments
+    flush_put_bits(&pb);
+    o += AES3_HEADER_LEN;
+
+    if (avctx->bits_per_raw_sample == 24) {
+        const uint32_t *samples = (uint32_t *)frame->data[0];
+
+        for (c = 0; c < frame->nb_samples; c++) {
+            uint8_t vucf = s->framing_index == 0 ? 0x10: 0;
+
+            for (channels = 0; channels < avctx->channels; channels += 2) {
+                o[0] = ff_reverse[(samples[0] & 0x0000FF00) >> 8];
+                o[1] = ff_reverse[(samples[0] & 0x00FF0000) >> 16];
+                o[2] = ff_reverse[(samples[0] & 0xFF000000) >> 24];
+                o[3] = ff_reverse[(samples[1] & 0x00000F00) >> 4] | vucf;
+                o[4] = ff_reverse[(samples[1] & 0x000FF000) >> 12];
+                o[5] = ff_reverse[(samples[1] & 0x0FF00000) >> 20];
+                o[6] = ff_reverse[(samples[1] & 0xF0000000) >> 28];
+                o += 7;
+                samples += 2;
+            }
+
+            s->framing_index++;
+            if (s->framing_index >= 192)
+                s->framing_index = 0;
+        }
+    } else if (avctx->bits_per_raw_sample == 20) {
+        const uint32_t *samples = (uint32_t *)frame->data[0];
+
+        for (c = 0; c < frame->nb_samples; c++) {
+            uint8_t vucf = s->framing_index == 0 ? 0x80: 0;
+
+            for (channels = 0; channels < avctx->channels; channels += 2) {
+                o[0] = ff_reverse[ (samples[0] & 0x000FF000) >> 12];
+                o[1] = ff_reverse[ (samples[0] & 0x0FF00000) >> 20];
+                o[2] = ff_reverse[((samples[0] & 0xF0000000) >> 28) | vucf];
+                o[3] = ff_reverse[ (samples[1] & 0x000FF000) >> 12];
+                o[4] = ff_reverse[ (samples[1] & 0x0FF00000) >> 20];
+                o[5] = ff_reverse[ (samples[1] & 0xF0000000) >> 28];
+                o += 6;
+                samples += 2;
+            }
+
+            s->framing_index++;
+            if (s->framing_index >= 192)
+                s->framing_index = 0;
+        }
+    } else if (avctx->bits_per_raw_sample == 16) {
+        const uint16_t *samples = (uint16_t *)frame->data[0];
+
+        for (c = 0; c < frame->nb_samples; c++) {
+            uint8_t vucf = s->framing_index == 0 ? 0x10 : 0;
+
+            for (channels = 0; channels < avctx->channels; channels += 2) {
+                o[0] = ff_reverse[ samples[0] & 0xFF];
+                o[1] = ff_reverse[(samples[0] & 0xFF00) >>  8];
+                o[2] = ff_reverse[(samples[1] & 0x0F)   <<  4] | vucf;
+                o[3] = ff_reverse[(samples[1] & 0x0FF0) >>  4];
+                o[4] = ff_reverse[(samples[1] & 0xF000) >> 12];
+                o += 5;
+                samples += 2;
+
+            }
+
+            s->framing_index++;
+            if (s->framing_index >= 192)
+                s->framing_index = 0;
+        }
+    }
+
+    *got_packet_ptr = 1;
+
+    return 0;
+}
+
+AVCodec ff_s302m_encoder = {
+    .name                  = "s302m",
+    .type                  = AVMEDIA_TYPE_AUDIO,
+    .id                    = CODEC_ID_S302M,
+    .priv_data_size        = sizeof(S302MEncContext),
+    .init                  = s302m_encode_init,
+    .encode2               = s302m_encode2_frame,
+    .long_name             = NULL_IF_CONFIG_SMALL("SMPTE 302M"),
+    .sample_fmts           = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S32,
+                                                            AV_SAMPLE_FMT_S16,
+                                                            AV_SAMPLE_FMT_NONE },
+    .capabilities          = CODEC_CAP_VARIABLE_FRAME_SIZE | CODEC_CAP_EXPERIMENTAL,
+    .supported_samplerates = (const int[]) { 48000, 0 },
+};