mirror of https://github.com/FFmpeg/FFmpeg.git
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/*
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* SMPTE 302M encoder |
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* Copyright (c) 2010 Google, Inc. |
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* Copyright (c) 2013 Darryl Wallace <wallacdj@gmail.com> |
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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 "internal.h" |
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#include "put_bits.h" |
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#define AES3_HEADER_LEN 4 |
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typedef struct S302MEncContext { |
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uint8_t framing_index; /* Set for even channels on multiple of 192 samples */ |
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} S302MEncContext; |
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static av_cold int s302m_encode_init(AVCodecContext *avctx) |
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{ |
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S302MEncContext *s = avctx->priv_data; |
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if (avctx->channels & 1 || avctx->channels > 8) { |
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av_log(avctx, AV_LOG_ERROR, |
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"Encoding %d channel(s) is not allowed. Only 2, 4, 6 and 8 channels are supported.\n", |
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avctx->channels); |
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return AVERROR(EINVAL); |
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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_raw_sample = 16; |
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break; |
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case AV_SAMPLE_FMT_S32: |
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if (avctx->bits_per_raw_sample > 24) { |
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av_log(avctx, AV_LOG_WARNING, "encoding as 24 bits-per-sample\n"); |
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avctx->bits_per_raw_sample = 24; |
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} else if (!avctx->bits_per_raw_sample) { |
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avctx->bits_per_raw_sample = 24; |
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} else if (avctx->bits_per_raw_sample <= 20) { |
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avctx->bits_per_raw_sample = 20; |
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} |
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} |
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avctx->frame_size = 0; |
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avctx->bit_rate = 48000 * avctx->channels * |
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(avctx->bits_per_raw_sample + 4); |
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s->framing_index = 0; |
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return 0; |
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} |
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static int s302m_encode2_frame(AVCodecContext *avctx, AVPacket *avpkt, |
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const AVFrame *frame, int *got_packet_ptr) |
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{ |
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S302MEncContext *s = avctx->priv_data; |
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const int buf_size = AES3_HEADER_LEN + |
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(frame->nb_samples * |
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avctx->channels * |
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(avctx->bits_per_raw_sample + 4)) / 8; |
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int ret, c, channels; |
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uint8_t *o; |
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PutBitContext pb; |
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if ((ret = ff_alloc_packet2(avctx, avpkt, buf_size)) < 0) |
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return ret; |
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o = avpkt->data; |
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init_put_bits(&pb, o, buf_size * 8); |
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put_bits(&pb, 16, buf_size - AES3_HEADER_LEN); |
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put_bits(&pb, 2, (avctx->channels - 2) >> 1); // number of channels
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put_bits(&pb, 8, 0); // channel ID
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put_bits(&pb, 2, (avctx->bits_per_raw_sample - 16) / 4); // bits per samples (0 = 16bit, 1 = 20bit, 2 = 24bit)
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put_bits(&pb, 4, 0); // alignments
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flush_put_bits(&pb); |
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o += AES3_HEADER_LEN; |
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if (avctx->bits_per_raw_sample == 24) { |
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const uint32_t *samples = (uint32_t *)frame->data[0]; |
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for (c = 0; c < frame->nb_samples; c++) { |
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uint8_t vucf = s->framing_index == 0 ? 0x10: 0; |
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for (channels = 0; channels < avctx->channels; channels += 2) { |
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o[0] = ff_reverse[(samples[0] & 0x0000FF00) >> 8]; |
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o[1] = ff_reverse[(samples[0] & 0x00FF0000) >> 16]; |
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o[2] = ff_reverse[(samples[0] & 0xFF000000) >> 24]; |
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o[3] = ff_reverse[(samples[1] & 0x00000F00) >> 4] | vucf; |
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o[4] = ff_reverse[(samples[1] & 0x000FF000) >> 12]; |
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o[5] = ff_reverse[(samples[1] & 0x0FF00000) >> 20]; |
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o[6] = ff_reverse[(samples[1] & 0xF0000000) >> 28]; |
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o += 7; |
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samples += 2; |
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} |
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s->framing_index++; |
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if (s->framing_index >= 192) |
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s->framing_index = 0; |
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} |
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} else if (avctx->bits_per_raw_sample == 20) { |
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const uint32_t *samples = (uint32_t *)frame->data[0]; |
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for (c = 0; c < frame->nb_samples; c++) { |
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uint8_t vucf = s->framing_index == 0 ? 0x80: 0; |
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for (channels = 0; channels < avctx->channels; channels += 2) { |
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o[0] = ff_reverse[ (samples[0] & 0x000FF000) >> 12]; |
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o[1] = ff_reverse[ (samples[0] & 0x0FF00000) >> 20]; |
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o[2] = ff_reverse[((samples[0] & 0xF0000000) >> 28) | vucf]; |
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o[3] = ff_reverse[ (samples[1] & 0x000FF000) >> 12]; |
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o[4] = ff_reverse[ (samples[1] & 0x0FF00000) >> 20]; |
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o[5] = ff_reverse[ (samples[1] & 0xF0000000) >> 28]; |
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o += 6; |
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samples += 2; |
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} |
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s->framing_index++; |
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if (s->framing_index >= 192) |
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s->framing_index = 0; |
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} |
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} else if (avctx->bits_per_raw_sample == 16) { |
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const uint16_t *samples = (uint16_t *)frame->data[0]; |
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for (c = 0; c < frame->nb_samples; c++) { |
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uint8_t vucf = s->framing_index == 0 ? 0x10 : 0; |
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for (channels = 0; channels < avctx->channels; channels += 2) { |
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o[0] = ff_reverse[ samples[0] & 0xFF]; |
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o[1] = ff_reverse[(samples[0] & 0xFF00) >> 8]; |
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o[2] = ff_reverse[(samples[1] & 0x0F) << 4] | vucf; |
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o[3] = ff_reverse[(samples[1] & 0x0FF0) >> 4]; |
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o[4] = ff_reverse[(samples[1] & 0xF000) >> 12]; |
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o += 5; |
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samples += 2; |
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} |
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s->framing_index++; |
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if (s->framing_index >= 192) |
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s->framing_index = 0; |
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} |
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} |
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*got_packet_ptr = 1; |
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return 0; |
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} |
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AVCodec ff_s302m_encoder = { |
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.name = "s302m", |
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.type = AVMEDIA_TYPE_AUDIO, |
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.id = CODEC_ID_S302M, |
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.priv_data_size = sizeof(S302MEncContext), |
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.init = s302m_encode_init, |
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.encode2 = s302m_encode2_frame, |
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.long_name = NULL_IF_CONFIG_SMALL("SMPTE 302M"), |
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.sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S32, |
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AV_SAMPLE_FMT_S16, |
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AV_SAMPLE_FMT_NONE }, |
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.capabilities = CODEC_CAP_VARIABLE_FRAME_SIZE | CODEC_CAP_EXPERIMENTAL, |
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.supported_samplerates = (const int[]) { 48000, 0 }, |
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}; |
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