/* * 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, frame_size; 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->bit_rate > 9800000) { av_log(avctx, AV_LOG_ERROR, "Too big bitrate: reduce sample rate, bitdepth or channels.\n"); return AVERROR(EINVAL); } if (avctx->sample_fmt == AV_SAMPLE_FMT_S16) { s->samples_per_block = 1; s->block_size = avctx->channels * 2; frame_size = 2008 / s->block_size; } 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; } frame_size = FFALIGN(2008 / s->block_size, s->samples_per_block); } s->header[0] = 0x0c; s->header[1] = (quant << 6) | (freq << 4) | (avctx->channels - 1); s->header[2] = 0x80; if (!avctx->frame_size) avctx->frame_size = frame_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; int blocks = (pkt_size - 3) / s->block_size; const int16_t *src16; const int32_t *src32; PutByteContext pb; int ret; if ((ret = ff_alloc_packet2(avctx, avpkt, pkt_size, 0)) < 0) return ret; memcpy(avpkt->data, s->header, 3); src16 = (const int16_t *)frame->data[0]; src32 = (const int32_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, *src16++); } while (--samples); break; case AV_SAMPLE_FMT_S32: if (avctx->channels == 1) { do { for (int i = 2; i; i--) { bytestream2_put_be16(&pb, src32[0] >> 16); bytestream2_put_be16(&pb, src32[1] >> 16); bytestream2_put_byte(&pb, (*src32++) >> 24); bytestream2_put_byte(&pb, (*src32++) >> 24); } } while (--blocks); } else { do { for (int i = s->groups_per_block; i; i--) { bytestream2_put_be16(&pb, src32[0] >> 16); bytestream2_put_be16(&pb, src32[1] >> 16); bytestream2_put_be16(&pb, src32[2] >> 16); bytestream2_put_be16(&pb, src32[3] >> 16); bytestream2_put_byte(&pb, (*src32++) >> 24); bytestream2_put_byte(&pb, (*src32++) >> 24); bytestream2_put_byte(&pb, (*src32++) >> 24); bytestream2_put_byte(&pb, (*src32++) >> 24); } } while (--blocks); } 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; } const 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, .encode2 = pcm_dvd_encode_frame, .capabilities = AV_CODEC_CAP_SMALL_LAST_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, AV_CH_LAYOUT_7POINT1, 0 }, .sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16, AV_SAMPLE_FMT_S32, AV_SAMPLE_FMT_NONE }, .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE, };