2 * LPCM codecs for PCM formats found in Video DVD streams
3 * Copyright (c) 2018 Paul B Mahol
5 * This file is part of FFmpeg.
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23 #include "bytestream.h"
26 typedef struct PCMDVDContext {
27 uint8_t header[3]; // Header added to every frame
28 int block_size; // Size of a block of samples in bytes
29 int samples_per_block; // Number of samples per channel per block
30 int groups_per_block; // Number of 20/24-bit sample groups per block
31 uint8_t *extra_samples; // Pointer to leftover samples from a frame
32 int extra_sample_count; // Number of leftover samples in the buffer
35 static av_cold int pcm_dvd_encode_init(AVCodecContext *avctx)
37 PCMDVDContext *s = avctx->priv_data;
38 int quant, freq, frame_size;
40 switch (avctx->sample_rate) {
49 switch (avctx->sample_fmt) {
50 case AV_SAMPLE_FMT_S16:
51 avctx->bits_per_coded_sample = 16;
54 case AV_SAMPLE_FMT_S32:
55 avctx->bits_per_coded_sample = 24;
60 avctx->bits_per_coded_sample = 16 + quant * 4;
61 avctx->block_align = avctx->channels * avctx->bits_per_coded_sample / 8;
62 avctx->bit_rate = avctx->block_align * 8LL * avctx->sample_rate;
63 if (avctx->bit_rate > 9800000) {
64 av_log(avctx, AV_LOG_ERROR, "Too big bitrate: reduce sample rate, bitdepth or channels.\n");
65 return AVERROR(EINVAL);
68 if (avctx->sample_fmt == AV_SAMPLE_FMT_S16) {
69 s->samples_per_block = 1;
70 s->block_size = avctx->channels * 2;
71 frame_size = 2008 / s->block_size;
73 switch (avctx->channels) {
77 /* one group has all the samples needed */
78 s->block_size = 4 * avctx->bits_per_coded_sample / 8;
79 s->samples_per_block = 4 / avctx->channels;
80 s->groups_per_block = 1;
83 /* two groups have all the samples needed */
84 s->block_size = 8 * avctx->bits_per_coded_sample / 8;
85 s->samples_per_block = 1;
86 s->groups_per_block = 2;
89 /* need avctx->channels groups */
90 s->block_size = 4 * avctx->channels *
91 avctx->bits_per_coded_sample / 8;
92 s->samples_per_block = 4;
93 s->groups_per_block = avctx->channels;
97 frame_size = FFALIGN(2008 / s->block_size, s->samples_per_block);
101 s->header[1] = (quant << 6) | (freq << 4) | (avctx->channels - 1);
104 if (!avctx->frame_size)
105 avctx->frame_size = frame_size;
110 static int pcm_dvd_encode_frame(AVCodecContext *avctx, AVPacket *avpkt,
111 const AVFrame *frame, int *got_packet_ptr)
113 PCMDVDContext *s = avctx->priv_data;
114 int samples = frame->nb_samples * avctx->channels;
115 int64_t pkt_size = (frame->nb_samples / s->samples_per_block) * s->block_size + 3;
116 int blocks = (pkt_size - 3) / s->block_size;
117 const int16_t *src16;
118 const int32_t *src32;
122 if ((ret = ff_alloc_packet2(avctx, avpkt, pkt_size, 0)) < 0)
125 memcpy(avpkt->data, s->header, 3);
127 src16 = (const int16_t *)frame->data[0];
128 src32 = (const int32_t *)frame->data[0];
130 bytestream2_init_writer(&pb, avpkt->data + 3, avpkt->size - 3);
132 switch (avctx->sample_fmt) {
133 case AV_SAMPLE_FMT_S16:
135 bytestream2_put_be16(&pb, *src16++);
138 case AV_SAMPLE_FMT_S32:
139 if (avctx->channels == 1) {
141 for (int i = 2; i; i--) {
142 bytestream2_put_be16(&pb, src32[0] >> 16);
143 bytestream2_put_be16(&pb, src32[1] >> 16);
144 bytestream2_put_byte(&pb, (*src32++) >> 24);
145 bytestream2_put_byte(&pb, (*src32++) >> 24);
150 for (int i = s->groups_per_block; i; i--) {
151 bytestream2_put_be16(&pb, src32[0] >> 16);
152 bytestream2_put_be16(&pb, src32[1] >> 16);
153 bytestream2_put_be16(&pb, src32[2] >> 16);
154 bytestream2_put_be16(&pb, src32[3] >> 16);
155 bytestream2_put_byte(&pb, (*src32++) >> 24);
156 bytestream2_put_byte(&pb, (*src32++) >> 24);
157 bytestream2_put_byte(&pb, (*src32++) >> 24);
158 bytestream2_put_byte(&pb, (*src32++) >> 24);
165 avpkt->pts = frame->pts;
166 avpkt->size = pkt_size;
167 avpkt->duration = ff_samples_to_time_base(avctx, frame->nb_samples);
173 static av_cold int pcm_dvd_encode_close(AVCodecContext *avctx)
178 AVCodec ff_pcm_dvd_encoder = {
180 .long_name = NULL_IF_CONFIG_SMALL("PCM signed 16|20|24-bit big-endian for DVD media"),
181 .type = AVMEDIA_TYPE_AUDIO,
182 .id = AV_CODEC_ID_PCM_DVD,
183 .priv_data_size = sizeof(PCMDVDContext),
184 .init = pcm_dvd_encode_init,
185 .close = pcm_dvd_encode_close,
186 .encode2 = pcm_dvd_encode_frame,
187 .capabilities = AV_CODEC_CAP_SMALL_LAST_FRAME,
188 .supported_samplerates = (const int[]) { 48000, 96000, 0},
189 .channel_layouts = (const uint64_t[]) { AV_CH_LAYOUT_MONO,
191 AV_CH_LAYOUT_5POINT1,
192 AV_CH_LAYOUT_7POINT1,
194 .sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16,
196 AV_SAMPLE_FMT_NONE },