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102 lines
2.9 KiB
102 lines
2.9 KiB
/* |
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* Raw AC-4 muxer |
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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 "libavcodec/codec_id.h" |
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#include "libavcodec/codec_par.h" |
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#include "libavcodec/packet.h" |
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#include "libavutil/crc.h" |
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#include "libavutil/opt.h" |
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#include "avformat.h" |
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#include "mux.h" |
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typedef struct AC4Context { |
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AVClass *class; |
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int write_crc; |
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} AC4Context; |
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static int ac4_init(AVFormatContext *s) |
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{ |
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AVCodecParameters *par = s->streams[0]->codecpar; |
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if (s->nb_streams != 1 || par->codec_id != AV_CODEC_ID_AC4) { |
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av_log(s, AV_LOG_ERROR, "Only one AC-4 stream can be muxed by the AC-4 muxer\n"); |
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return AVERROR(EINVAL); |
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} |
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return 0; |
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} |
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static int ac4_write_packet(AVFormatContext *s, AVPacket *pkt) |
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{ |
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AC4Context *ac4 = s->priv_data; |
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AVIOContext *pb = s->pb; |
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if (!pkt->size) |
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return 0; |
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if (ac4->write_crc) |
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avio_wb16(pb, 0xAC41); |
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else |
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avio_wb16(pb, 0xAC40); |
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if (pkt->size >= 0xffff) { |
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avio_wb16(pb, 0xffff); |
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avio_wb24(pb, pkt->size); |
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} else { |
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avio_wb16(pb, pkt->size); |
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} |
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avio_write(pb, pkt->data, pkt->size); |
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if (ac4->write_crc) { |
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uint16_t crc = av_crc(av_crc_get_table(AV_CRC_16_ANSI), 0, pkt->data, pkt->size); |
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avio_wl16(pb, crc); |
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} |
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return 0; |
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} |
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#define ENC AV_OPT_FLAG_ENCODING_PARAM |
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#define OFFSET(obj) offsetof(AC4Context, obj) |
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static const AVOption ac4_options[] = { |
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{ "write_crc", "enable checksum", OFFSET(write_crc), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, ENC}, |
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{ NULL }, |
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}; |
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static const AVClass ac4_muxer_class = { |
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.class_name = "AC4 muxer", |
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.item_name = av_default_item_name, |
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.option = ac4_options, |
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.version = LIBAVUTIL_VERSION_INT, |
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}; |
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const FFOutputFormat ff_ac4_muxer = { |
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.p.name = "ac4", |
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.p.long_name = NULL_IF_CONFIG_SMALL("raw AC-4"), |
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.p.mime_type = "audio/ac4", |
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.p.extensions = "ac4", |
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.priv_data_size = sizeof(AC4Context), |
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.p.audio_codec = AV_CODEC_ID_AC4, |
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.p.video_codec = AV_CODEC_ID_NONE, |
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.init = ac4_init, |
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.write_packet = ac4_write_packet, |
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.p.priv_class = &ac4_muxer_class, |
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.p.flags = AVFMT_NOTIMESTAMPS, |
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};
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