mirror of https://github.com/FFmpeg/FFmpeg.git
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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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