[FFmpeg-devel] [PATCH] s302m encoder
Paul B Mahol
onemda at gmail.com
Sat Apr 20 00:11:56 CEST 2013
From: Darryl Wallace <wallacdj at gmail.com>
Signed-off-by: Paul B Mahol <onemda at gmail.com>
---
TODO: proper frame->nb_samples calculation, current one does not follow specification.
---
doc/general.texi | 2 +-
libavcodec/Makefile | 1 +
libavcodec/allcodecs.c | 2 +-
libavcodec/s302menc.c | 187 +++++++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 190 insertions(+), 2 deletions(-)
create mode 100644 libavcodec/s302menc.c
diff --git a/doc/general.texi b/doc/general.texi
index 39b9360..0b1cade 100644
--- a/doc/general.texi
+++ b/doc/general.texi
@@ -886,7 +886,7 @@ following image formats are supported:
@item Sierra VMD audio @tab @tab X
@tab Used in Sierra VMD files.
@item Smacker audio @tab @tab X
- at item SMPTE 302M AES3 audio @tab @tab X
+ at item SMPTE 302M AES3 audio @tab X @tab X
@item Sonic @tab X @tab X
@tab experimental codec
@item Sonic lossless @tab X @tab X
diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index ac342b1..59c756d 100644
--- a/libavcodec/Makefile
+++ b/libavcodec/Makefile
@@ -372,6 +372,7 @@ OBJS-$(CONFIG_RV30_DECODER) += rv30.o rv34.o rv30dsp.o rv34dsp.o
OBJS-$(CONFIG_RV40_DECODER) += rv40.o rv34.o rv34dsp.o rv40dsp.o
OBJS-$(CONFIG_SAMI_DECODER) += samidec.o ass.o
OBJS-$(CONFIG_S302M_DECODER) += s302m.o
+OBJS-$(CONFIG_S302M_ENCODER) += s302menc.o
OBJS-$(CONFIG_SANM_DECODER) += sanm.o
OBJS-$(CONFIG_SGI_DECODER) += sgidec.o
OBJS-$(CONFIG_SGI_ENCODER) += sgienc.o rle.o
diff --git a/libavcodec/allcodecs.c b/libavcodec/allcodecs.c
index 19a638c..eeb6324 100644
--- a/libavcodec/allcodecs.c
+++ b/libavcodec/allcodecs.c
@@ -237,7 +237,7 @@ void avcodec_register_all(void)
REGISTER_ENCDEC (RV20, rv20);
REGISTER_DECODER(RV30, rv30);
REGISTER_DECODER(RV40, rv40);
- REGISTER_DECODER(S302M, s302m);
+ REGISTER_ENCDEC (S302M, s302m);
REGISTER_DECODER(SANM, sanm);
REGISTER_ENCDEC (SGI, sgi);
REGISTER_DECODER(SGIRLE, sgirle);
diff --git a/libavcodec/s302menc.c b/libavcodec/s302menc.c
new file mode 100644
index 0000000..dbfbbff
--- /dev/null
+++ b/libavcodec/s302menc.c
@@ -0,0 +1,187 @@
+/*
+ * SMPTE 302M encoder
+ * Copyright (c) 2010, Google, Inc.
+ * Copyright (c) 2013, Darryl Wallace <wallacdj at gmail.com>
+ *
+ * This file is part of Libav.
+ *
+ * Libav 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.
+ *
+ * Libav 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 Libav; 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);
+ }
+
+ if (avctx->bits_per_coded_sample == 0) {
+ if (avctx->sample_fmt == AV_SAMPLE_FMT_S32) {
+ avctx->bits_per_coded_sample = 24;
+ } else if (avctx->sample_fmt == AV_SAMPLE_FMT_S16) {
+ avctx->bits_per_coded_sample = 16;
+ }
+ } else if (avctx->bits_per_coded_sample == 24 ||
+ avctx->bits_per_coded_sample == 20) {
+ avctx->sample_fmt = AV_SAMPLE_FMT_S32;
+ } else if(avctx->bits_per_coded_sample == 16) {
+ avctx->sample_fmt = AV_SAMPLE_FMT_S16;
+ } else {
+ av_log(avctx, AV_LOG_ERROR,
+ "Unsupported bits per coded sample of %d.\n",
+ avctx->bits_per_coded_sample);
+ return AVERROR(EINVAL);
+ }
+
+ avctx->frame_size = 0;
+ avctx->bit_rate = 48000 * avctx->channels *
+ (avctx->bits_per_coded_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_coded_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_coded_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_coded_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_coded_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_coded_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;
+}
+
+static const uint64_t s302m_channel_layout[] = {
+ AV_CH_LAYOUT_STEREO,
+ AV_CH_LAYOUT_QUAD,
+ AV_CH_LAYOUT_5POINT1_BACK,
+ AV_CH_LAYOUT_5POINT1_BACK | AV_CH_LAYOUT_STEREO_DOWNMIX,
+ 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,
+ .supported_samplerates = (const int[]) { 48000, 0 },
+ .channel_layouts = s302m_channel_layout,
+};
--
1.7.11.2
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