[FFmpeg-devel] [PATCH] avcodec: add PCM-DVD encoder
Paul B Mahol
onemda at gmail.com
Mon Nov 26 21:48:37 EET 2018
TODO: add >16 bit support, needs to muxer update.
Signed-off-by: Paul B Mahol <onemda at gmail.com>
---
libavcodec/Makefile | 1 +
libavcodec/allcodecs.c | 1 +
libavcodec/pcm-dvdenc.c | 159 ++++++++++++++++++++++++++++++++++++++++
3 files changed, 161 insertions(+)
create mode 100644 libavcodec/pcm-dvdenc.c
diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index 2840a8069f..5feadac729 100644
--- a/libavcodec/Makefile
+++ b/libavcodec/Makefile
@@ -737,6 +737,7 @@ OBJS-$(CONFIG_PCM_ALAW_DECODER) += pcm.o
OBJS-$(CONFIG_PCM_ALAW_ENCODER) += pcm.o
OBJS-$(CONFIG_PCM_BLURAY_DECODER) += pcm-bluray.o
OBJS-$(CONFIG_PCM_DVD_DECODER) += pcm-dvd.o
+OBJS-$(CONFIG_PCM_DVD_ENCODER) += pcm-dvdenc.o
OBJS-$(CONFIG_PCM_F16LE_DECODER) += pcm.o
OBJS-$(CONFIG_PCM_F24LE_DECODER) += pcm.o
OBJS-$(CONFIG_PCM_F32BE_DECODER) += pcm.o
diff --git a/libavcodec/allcodecs.c b/libavcodec/allcodecs.c
index 2c17db5a70..d70646e91a 100644
--- a/libavcodec/allcodecs.c
+++ b/libavcodec/allcodecs.c
@@ -494,6 +494,7 @@ extern AVCodec ff_xma2_decoder;
extern AVCodec ff_pcm_alaw_encoder;
extern AVCodec ff_pcm_alaw_decoder;
extern AVCodec ff_pcm_bluray_decoder;
+extern AVCodec ff_pcm_dvd_encoder;
extern AVCodec ff_pcm_dvd_decoder;
extern AVCodec ff_pcm_f16le_decoder;
extern AVCodec ff_pcm_f24le_decoder;
diff --git a/libavcodec/pcm-dvdenc.c b/libavcodec/pcm-dvdenc.c
new file mode 100644
index 0000000000..536b27dce6
--- /dev/null
+++ b/libavcodec/pcm-dvdenc.c
@@ -0,0 +1,159 @@
+/*
+ * LPCM codecs for PCM formats found in Video DVD streams
+ * Copyright (c) 2018 Paul B Mahol
+ *
+ * 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 "bytestream.h"
+#include "internal.h"
+
+typedef struct PCMDVDContext {
+ uint8_t header[3]; // Header added to every frame
+ int block_size; // Size of a block of samples in bytes
+ int samples_per_block; // Number of samples per channel per block
+ int groups_per_block; // Number of 20/24-bit sample groups per block
+ uint8_t *extra_samples; // Pointer to leftover samples from a frame
+ int extra_sample_count; // Number of leftover samples in the buffer
+} PCMDVDContext;
+
+static av_cold int pcm_dvd_encode_init(AVCodecContext *avctx)
+{
+ PCMDVDContext *s = avctx->priv_data;
+ int quant, freq;
+
+ switch (avctx->sample_rate) {
+ case 48000:
+ freq = 0;
+ break;
+ case 96000:
+ freq = 1;
+ break;
+ }
+
+ switch (avctx->sample_fmt) {
+ case AV_SAMPLE_FMT_S16:
+ avctx->bits_per_coded_sample = 16;
+ quant = 0;
+ break;
+ case AV_SAMPLE_FMT_S32:
+ avctx->bits_per_coded_sample = 24;
+ quant = 2;
+ break;
+ }
+
+ avctx->bits_per_coded_sample = 16 + quant * 4;
+ avctx->block_align = avctx->channels * avctx->bits_per_coded_sample / 8;
+ avctx->bit_rate = avctx->block_align * 8LL * avctx->sample_rate;
+
+ if (avctx->sample_fmt == AV_SAMPLE_FMT_S16) {
+ s->samples_per_block = 1;
+ s->block_size = avctx->channels * 2;
+ } else {
+ switch (avctx->channels) {
+ case 1:
+ case 2:
+ case 4:
+ /* one group has all the samples needed */
+ s->block_size = 4 * avctx->bits_per_coded_sample / 8;
+ s->samples_per_block = 4 / avctx->channels;
+ s->groups_per_block = 1;
+ break;
+ case 8:
+ /* two groups have all the samples needed */
+ s->block_size = 8 * avctx->bits_per_coded_sample / 8;
+ s->samples_per_block = 1;
+ s->groups_per_block = 2;
+ break;
+ default:
+ /* need avctx->channels groups */
+ s->block_size = 4 * avctx->channels *
+ avctx->bits_per_coded_sample / 8;
+ s->samples_per_block = 4;
+ s->groups_per_block = avctx->channels;
+ break;
+ }
+ }
+
+ s->header[0] = 0x0c;
+ s->header[1] = (quant << 6) | (freq << 4) | (avctx->channels - 1);
+ s->header[2] = 0x80;
+
+ avctx->frame_size = 2008 / s->block_size;
+
+ return 0;
+}
+
+static int pcm_dvd_encode_frame(AVCodecContext *avctx, AVPacket *avpkt,
+ const AVFrame *frame, int *got_packet_ptr)
+{
+ PCMDVDContext *s = avctx->priv_data;
+ int samples = frame->nb_samples * avctx->channels;
+ int64_t pkt_size = (frame->nb_samples / s->samples_per_block) * s->block_size + 3;
+ const uint16_t *src;
+ PutByteContext pb;
+ int ret;
+
+ if ((ret = ff_alloc_packet2(avctx, avpkt, pkt_size, 0)) < 0)
+ return ret;
+
+ memcpy(avpkt->data, s->header, 3);
+
+ src = (const int16_t *)frame->data[0];
+
+ bytestream2_init_writer(&pb, avpkt->data + 3, avpkt->size - 3);
+
+ switch (avctx->sample_fmt) {
+ case AV_SAMPLE_FMT_S16:
+ do {
+ bytestream2_put_be16(&pb, *src++);
+ } while (--samples);
+ break;
+ }
+
+ avpkt->pts = frame->pts;
+ avpkt->size = pkt_size;
+ avpkt->duration = ff_samples_to_time_base(avctx, frame->nb_samples);
+ *got_packet_ptr = 1;
+
+ return 0;
+}
+
+static av_cold int pcm_dvd_encode_close(AVCodecContext *avctx)
+{
+ return 0;
+}
+
+AVCodec ff_pcm_dvd_encoder = {
+ .name = "pcm_dvd",
+ .long_name = NULL_IF_CONFIG_SMALL("PCM signed 16|20|24-bit big-endian for DVD media"),
+ .type = AVMEDIA_TYPE_AUDIO,
+ .id = AV_CODEC_ID_PCM_DVD,
+ .priv_data_size = sizeof(PCMDVDContext),
+ .init = pcm_dvd_encode_init,
+ .close = pcm_dvd_encode_close,
+ .encode2 = pcm_dvd_encode_frame,
+ .supported_samplerates = (const int[]) { 48000, 96000, 0},
+ .channel_layouts = (const uint64_t[]) { AV_CH_LAYOUT_MONO,
+ AV_CH_LAYOUT_STEREO,
+ AV_CH_LAYOUT_5POINT1,
+ 0 },
+ .sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16,
+ AV_SAMPLE_FMT_S32,
+ AV_SAMPLE_FMT_NONE },
+};
--
2.17.1
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