mirror of https://github.com/FFmpeg/FFmpeg.git
extended ADPCM decoder by ISS specific IMA variant Originally committed as revision 16658 to svn://svn.ffmpeg.org/ffmpeg/trunkpull/126/head
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9 changed files with 169 additions and 2 deletions
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/*
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* ISS (.iss) file demuxer |
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* Copyright (c) 2008 Jaikrishnan Menon <realityman@gmx.net> |
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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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/**
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* @file iss.c |
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* Funcom ISS file demuxer |
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* @author Jaikrishnan Menon |
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* for more information on the .iss file format, visit: |
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* http://wiki.multimedia.cx/index.php?title=FunCom_ISS
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*/ |
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#include "avformat.h" |
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#include "libavutil/avstring.h" |
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#define ISS_SIG "IMA_ADPCM_Sound" |
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#define ISS_SIG_LEN 15 |
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#define MAX_TOKEN_SIZE 20 |
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typedef struct { |
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int packet_size; |
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int sample_start_pos; |
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} IssDemuxContext; |
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static void get_token(ByteIOContext *s, char *buf, int maxlen) |
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{ |
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int i = 0; |
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char c; |
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while ((c = get_byte(s))) { |
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if(c == ' ') |
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break; |
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if (i < maxlen-1) |
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buf[i++] = c; |
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} |
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buf[i] = 0; /* Ensure null terminated, but may be truncated */ |
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} |
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static int iss_probe(AVProbeData *p) |
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{ |
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if (strncmp(p->buf, ISS_SIG, ISS_SIG_LEN)) |
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return 0; |
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return AVPROBE_SCORE_MAX; |
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} |
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static av_cold int iss_read_header(AVFormatContext *s, AVFormatParameters *ap) |
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{ |
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IssDemuxContext *iss = s->priv_data; |
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ByteIOContext *pb = s->pb; |
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AVStream *st; |
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char token[MAX_TOKEN_SIZE]; |
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int stereo, rate_divisor; |
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get_token(pb, token, sizeof(token)); //"IMA_ADPCM_Sound"
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get_token(pb, token, sizeof(token)); //packet size
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sscanf(token, "%d", &iss->packet_size); |
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get_token(pb, token, sizeof(token)); //File ID
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get_token(pb, token, sizeof(token)); //out size
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get_token(pb, token, sizeof(token)); //stereo
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sscanf(token, "%d", &stereo); |
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get_token(pb, token, sizeof(token)); //Unknown1
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get_token(pb, token, sizeof(token)); //RateDivisor
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sscanf(token, "%d", &rate_divisor); |
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get_token(pb, token, sizeof(token)); //Unknown2
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get_token(pb, token, sizeof(token)); //Version ID
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get_token(pb, token, sizeof(token)); //Size
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iss->sample_start_pos = url_ftell(pb); |
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st = av_new_stream(s, 0); |
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if (!st) |
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return AVERROR(ENOMEM); |
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st->codec->codec_type = CODEC_TYPE_AUDIO; |
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st->codec->codec_id = CODEC_ID_ADPCM_IMA_ISS; |
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st->codec->channels = stereo ? 2 : 1; |
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st->codec->sample_rate = 44100; |
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if(rate_divisor > 0) |
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st->codec->sample_rate /= rate_divisor; |
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st->codec->bits_per_coded_sample = 4; |
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st->codec->bit_rate = st->codec->channels * st->codec->sample_rate |
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* st->codec->bits_per_coded_sample; |
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st->codec->block_align = iss->packet_size; |
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av_set_pts_info(st, 32, 1, st->codec->sample_rate); |
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return 0; |
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} |
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static int iss_read_packet(AVFormatContext *s, AVPacket *pkt) |
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{ |
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IssDemuxContext *iss = s->priv_data; |
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int ret = av_get_packet(s->pb, pkt, iss->packet_size); |
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if(ret < 0) |
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return ret; |
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pkt->stream_index = 0; |
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pkt->pts = url_ftell(s->pb) - iss->sample_start_pos; |
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if(s->streams[0]->codec->channels > 0) |
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pkt->pts /= s->streams[0]->codec->channels*2; |
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return 0; |
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} |
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AVInputFormat iss_demuxer = { |
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"ISS", |
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NULL_IF_CONFIG_SMALL("Funcom ISS format"), |
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sizeof(IssDemuxContext), |
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iss_probe, |
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iss_read_header, |
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iss_read_packet, |
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}; |
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