198 lines
6.9 KiB
C
198 lines
6.9 KiB
C
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/*
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* LPCM codecs for PCM formats found in Video DVD streams
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* Copyright (c) 2018 Paul B Mahol
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "avcodec.h"
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#include "bytestream.h"
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#include "internal.h"
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typedef struct PCMDVDContext {
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uint8_t header[3]; // Header added to every frame
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int block_size; // Size of a block of samples in bytes
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int samples_per_block; // Number of samples per channel per block
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int groups_per_block; // Number of 20/24-bit sample groups per block
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uint8_t *extra_samples; // Pointer to leftover samples from a frame
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int extra_sample_count; // Number of leftover samples in the buffer
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} PCMDVDContext;
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static av_cold int pcm_dvd_encode_init(AVCodecContext *avctx)
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{
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PCMDVDContext *s = avctx->priv_data;
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int quant, freq, frame_size;
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switch (avctx->sample_rate) {
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case 48000:
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freq = 0;
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break;
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case 96000:
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freq = 1;
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break;
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}
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switch (avctx->sample_fmt) {
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case AV_SAMPLE_FMT_S16:
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avctx->bits_per_coded_sample = 16;
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quant = 0;
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break;
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case AV_SAMPLE_FMT_S32:
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avctx->bits_per_coded_sample = 24;
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quant = 2;
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break;
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}
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avctx->bits_per_coded_sample = 16 + quant * 4;
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avctx->block_align = avctx->channels * avctx->bits_per_coded_sample / 8;
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avctx->bit_rate = avctx->block_align * 8LL * avctx->sample_rate;
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if (avctx->bit_rate > 9800000) {
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av_log(avctx, AV_LOG_ERROR, "Too big bitrate: reduce sample rate, bitdepth or channels.\n");
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return AVERROR(EINVAL);
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}
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if (avctx->sample_fmt == AV_SAMPLE_FMT_S16) {
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s->samples_per_block = 1;
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s->block_size = avctx->channels * 2;
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frame_size = 2008 / s->block_size;
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} else {
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switch (avctx->channels) {
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case 1:
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case 2:
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case 4:
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/* one group has all the samples needed */
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s->block_size = 4 * avctx->bits_per_coded_sample / 8;
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s->samples_per_block = 4 / avctx->channels;
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s->groups_per_block = 1;
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break;
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case 8:
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/* two groups have all the samples needed */
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s->block_size = 8 * avctx->bits_per_coded_sample / 8;
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s->samples_per_block = 1;
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s->groups_per_block = 2;
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break;
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default:
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/* need avctx->channels groups */
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s->block_size = 4 * avctx->channels *
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avctx->bits_per_coded_sample / 8;
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s->samples_per_block = 4;
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s->groups_per_block = avctx->channels;
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break;
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}
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frame_size = FFALIGN(2008 / s->block_size, s->samples_per_block);
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}
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s->header[0] = 0x0c;
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s->header[1] = (quant << 6) | (freq << 4) | (avctx->channels - 1);
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s->header[2] = 0x80;
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if (!avctx->frame_size)
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avctx->frame_size = frame_size;
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return 0;
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}
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static int pcm_dvd_encode_frame(AVCodecContext *avctx, AVPacket *avpkt,
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const AVFrame *frame, int *got_packet_ptr)
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{
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PCMDVDContext *s = avctx->priv_data;
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int samples = frame->nb_samples * avctx->channels;
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int64_t pkt_size = (frame->nb_samples / s->samples_per_block) * s->block_size + 3;
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int blocks = (pkt_size - 3) / s->block_size;
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const int16_t *src16;
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const int32_t *src32;
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PutByteContext pb;
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int ret;
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if ((ret = ff_alloc_packet2(avctx, avpkt, pkt_size, 0)) < 0)
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return ret;
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memcpy(avpkt->data, s->header, 3);
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src16 = (const int16_t *)frame->data[0];
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src32 = (const int32_t *)frame->data[0];
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bytestream2_init_writer(&pb, avpkt->data + 3, avpkt->size - 3);
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switch (avctx->sample_fmt) {
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case AV_SAMPLE_FMT_S16:
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do {
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bytestream2_put_be16(&pb, *src16++);
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} while (--samples);
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break;
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case AV_SAMPLE_FMT_S32:
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if (avctx->channels == 1) {
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do {
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for (int i = 2; i; i--) {
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bytestream2_put_be16(&pb, src32[0] >> 16);
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bytestream2_put_be16(&pb, src32[1] >> 16);
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bytestream2_put_byte(&pb, (*src32++) >> 24);
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bytestream2_put_byte(&pb, (*src32++) >> 24);
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}
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} while (--blocks);
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} else {
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do {
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for (int i = s->groups_per_block; i; i--) {
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bytestream2_put_be16(&pb, src32[0] >> 16);
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bytestream2_put_be16(&pb, src32[1] >> 16);
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bytestream2_put_be16(&pb, src32[2] >> 16);
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bytestream2_put_be16(&pb, src32[3] >> 16);
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bytestream2_put_byte(&pb, (*src32++) >> 24);
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bytestream2_put_byte(&pb, (*src32++) >> 24);
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bytestream2_put_byte(&pb, (*src32++) >> 24);
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bytestream2_put_byte(&pb, (*src32++) >> 24);
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}
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} while (--blocks);
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}
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break;
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}
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avpkt->pts = frame->pts;
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avpkt->size = pkt_size;
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avpkt->duration = ff_samples_to_time_base(avctx, frame->nb_samples);
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*got_packet_ptr = 1;
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return 0;
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}
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static av_cold int pcm_dvd_encode_close(AVCodecContext *avctx)
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{
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return 0;
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}
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AVCodec ff_pcm_dvd_encoder = {
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.name = "pcm_dvd",
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.long_name = NULL_IF_CONFIG_SMALL("PCM signed 16|20|24-bit big-endian for DVD media"),
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.type = AVMEDIA_TYPE_AUDIO,
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.id = AV_CODEC_ID_PCM_DVD,
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.priv_data_size = sizeof(PCMDVDContext),
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.init = pcm_dvd_encode_init,
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.close = pcm_dvd_encode_close,
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.encode2 = pcm_dvd_encode_frame,
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.capabilities = AV_CODEC_CAP_SMALL_LAST_FRAME,
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.supported_samplerates = (const int[]) { 48000, 96000, 0},
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.channel_layouts = (const uint64_t[]) { AV_CH_LAYOUT_MONO,
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AV_CH_LAYOUT_STEREO,
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AV_CH_LAYOUT_5POINT1,
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AV_CH_LAYOUT_7POINT1,
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0 },
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.sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16,
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AV_SAMPLE_FMT_S32,
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AV_SAMPLE_FMT_NONE },
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};
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