libavformat/sdns.c

   1 /*
   2  * SDNS demuxer
   3  * Copyright (c) 2023 Paul B Mahol
   4  *
   5  * This file is part of FFmpeg.
   6  *
   7  * FFmpeg is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * FFmpeg is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with FFmpeg; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 #include "libavutil/channel_layout.h"
  23 #include "libavutil/intreadwrite.h"
  24 #include "avformat.h"
  25 #include "demux.h"
  26 #include "internal.h"
  27
  28 static int sdns_probe(const AVProbeData *p)
  29 {
  30     if (AV_RL32(p->buf) != MKTAG('S','D','N','S'))
  31         return 0;
  32     if (AV_RB32(p->buf + 8) <= 0)
  33         return 0;
  34     if (AV_RB32(p->buf + 12) <= 0 ||
  35         AV_RB32(p->buf + 12) > 128)
  36         return 0;
  37     return AVPROBE_SCORE_MAX / 3;
  38 }
  39
  40 static int sdns_read_header(AVFormatContext *s)
  41 {
  42     AVIOContext *pb = s->pb;
  43     AVCodecParameters *par;
  44     int channels, ret;
  45     AVStream *st;
  46
  47     avio_skip(pb, 8);
  48
  49     st = avformat_new_stream(s, NULL);
  50     if (!st)
  51         return AVERROR(ENOMEM);
  52
  53     par              = st->codecpar;
  54     par->codec_type  = AVMEDIA_TYPE_AUDIO;
  55     par->codec_id    = AV_CODEC_ID_XMA1;
  56     par->sample_rate = avio_rb32(pb);
  57     channels         = avio_rb32(pb);
  58     if (channels <= 0 || channels > 128)
  59         return AVERROR_INVALIDDATA;
  60     av_channel_layout_default(&par->ch_layout, channels);
  61     if (par->sample_rate <= 0)
  62         return AVERROR_INVALIDDATA;
  63     par->block_align = 2048;
  64     if ((ret = ff_alloc_extradata(par, 8 + 20 * ((channels + 1) / 2))) < 0)
  65         return ret;
  66     memset(par->extradata, 0, 28);
  67     par->extradata[4] = (channels + 1) / 2;
  68     for (int i = 0; i < par->extradata[4]; i++)
  69         par->extradata[8 + 20 * i + 17] = FFMIN(2, channels - i * 2);
  70     avpriv_set_pts_info(st, 64, 1, par->sample_rate);
  71     avio_seek(pb, 0x1000, SEEK_SET);
  72
  73     return 0;
  74 }
  75
  76 static int sdns_read_packet(AVFormatContext *s, AVPacket *pkt)
  77 {
  78     int ret;
  79
  80     if (avio_feof(s->pb))
  81         return AVERROR_EOF;
  82     ret = av_get_packet(s->pb, pkt, 2048);
  83     pkt->stream_index = 0;
  84
  85     return ret;
  86 }
  87
  88 const FFInputFormat ff_sdns_demuxer = {
  89     .p.name         = "sdns",
  90     .p.long_name    = NULL_IF_CONFIG_SMALL("Xbox SDNS"),
  91     .p.flags        = AVFMT_GENERIC_INDEX,
  92     .p.extensions   = "sdns",
  93     .read_probe     = sdns_probe,
  94     .read_header    = sdns_read_header,
  95     .read_packet    = sdns_read_packet,
  96 };