libavformat/kvag.c

   1 /*
   2  * Simon & Schuster Interactive VAG (de)muxer
   3  *
   4  * Copyright (C) 2020 Zane van Iperen (zane@zanevaniperen.com)
   5  *
   6  * This file is part of FFmpeg.
   7  *
   8  * FFmpeg is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; either
  11  * version 2.1 of the License, or (at your option) any later version.
  12  *
  13  * FFmpeg is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with FFmpeg; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  21  */
  22
  23 #include "config_components.h"
  24
  25 #include "libavutil/channel_layout.h"
  26 #include "avformat.h"
  27 #include "avio_internal.h"
  28 #include "demux.h"
  29 #include "internal.h"
  30 #include "mux.h"
  31 #include "rawenc.h"
  32 #include "libavutil/intreadwrite.h"
  33
  34 #define KVAG_TAG            MKTAG('K', 'V', 'A', 'G')
  35 #define KVAG_HEADER_SIZE    14
  36 #define KVAG_MAX_READ_SIZE  4096
  37
  38 typedef struct KVAGHeader {
  39     uint32_t    magic;
  40     uint32_t    data_size;
  41     int    sample_rate;
  42     uint16_t    stereo;
  43 } KVAGHeader;
  44
  45 #if CONFIG_KVAG_DEMUXER
  46 static int kvag_probe(const AVProbeData *p)
  47 {
  48     if (AV_RL32(p->buf) != KVAG_TAG)
  49         return 0;
  50
  51     return AVPROBE_SCORE_EXTENSION + 1;
  52 }
  53
  54 static int kvag_read_header(AVFormatContext *s)
  55 {
  56     int ret;
  57     AVStream *st;
  58     KVAGHeader hdr;
  59     AVCodecParameters *par;
  60     uint8_t buf[KVAG_HEADER_SIZE];
  61
  62     if (!(st = avformat_new_stream(s, NULL)))
  63         return AVERROR(ENOMEM);
  64
  65     if ((ret = ffio_read_size(s->pb, buf, KVAG_HEADER_SIZE)) < 0)
  66         return ret;
  67
  68     hdr.magic                   = AV_RL32(buf +  0);
  69     hdr.data_size               = AV_RL32(buf +  4);
  70     hdr.sample_rate             = AV_RL32(buf +  8);
  71     hdr.stereo                  = AV_RL16(buf + 12);
  72
  73     if (hdr.sample_rate <= 0)
  74         return AVERROR_INVALIDDATA;
  75
  76     par                         = st->codecpar;
  77     par->codec_type             = AVMEDIA_TYPE_AUDIO;
  78     par->codec_id               = AV_CODEC_ID_ADPCM_IMA_SSI;
  79     par->format                 = AV_SAMPLE_FMT_S16;
  80
  81     av_channel_layout_default(&par->ch_layout, !!hdr.stereo + 1);
  82     par->sample_rate            = hdr.sample_rate;
  83     par->bits_per_coded_sample  = 4;
  84     par->block_align            = 1;
  85     par->bit_rate               = par->ch_layout.nb_channels *
  86                                   (uint64_t)par->sample_rate *
  87                                   par->bits_per_coded_sample;
  88
  89     avpriv_set_pts_info(st, 64, 1, par->sample_rate);
  90     st->start_time              = 0;
  91     st->duration                = hdr.data_size *
  92                                   (8 / par->bits_per_coded_sample) /
  93                                   par->ch_layout.nb_channels;
  94
  95     return 0;
  96 }
  97
  98 static int kvag_read_packet(AVFormatContext *s, AVPacket *pkt)
  99 {
 100     int ret;
 101     AVCodecParameters *par = s->streams[0]->codecpar;
 102
 103     if ((ret = av_get_packet(s->pb, pkt, KVAG_MAX_READ_SIZE)) < 0)
 104         return ret;
 105
 106     pkt->flags          &= ~AV_PKT_FLAG_CORRUPT;
 107     pkt->stream_index   = 0;
 108     pkt->duration       = ret * (8 / par->bits_per_coded_sample) / par->ch_layout.nb_channels;
 109
 110     return 0;
 111 }
 112
 113 static int kvag_seek(AVFormatContext *s, int stream_index,
 114                      int64_t pts, int flags)
 115 {
 116     if (pts != 0)
 117         return AVERROR(EINVAL);
 118
 119     return avio_seek(s->pb, KVAG_HEADER_SIZE, SEEK_SET);
 120 }
 121
 122 const FFInputFormat ff_kvag_demuxer = {
 123     .p.name         = "kvag",
 124     .p.long_name    = NULL_IF_CONFIG_SMALL("Simon & Schuster Interactive VAG"),
 125     .read_probe     = kvag_probe,
 126     .read_header    = kvag_read_header,
 127     .read_packet    = kvag_read_packet,
 128     .read_seek      = kvag_seek,
 129 };
 130 #endif
 131
 132 #if CONFIG_KVAG_MUXER
 133 static int kvag_write_init(AVFormatContext *s)
 134 {
 135     AVCodecParameters *par = s->streams[0]->codecpar;
 136
 137     if (par->ch_layout.nb_channels > 2) {
 138         av_log(s, AV_LOG_ERROR, "KVAG files only support up to 2 channels\n");
 139         return AVERROR(EINVAL);
 140     }
 141
 142     if (!(s->pb->seekable & AVIO_SEEKABLE_NORMAL)) {
 143         av_log(s, AV_LOG_WARNING, "Stream not seekable, unable to write output file\n");
 144         return AVERROR(EINVAL);
 145     }
 146
 147     return 0;
 148 }
 149
 150 static int kvag_write_header(AVFormatContext *s)
 151 {
 152     uint8_t buf[KVAG_HEADER_SIZE];
 153     AVCodecParameters *par = s->streams[0]->codecpar;
 154
 155     AV_WL32(buf +  0, KVAG_TAG);
 156     AV_WL32(buf +  4, 0); /* Data size, we fix this up later. */
 157     AV_WL32(buf +  8, par->sample_rate);
 158     AV_WL16(buf + 12, par->ch_layout.nb_channels == 2);
 159
 160     avio_write(s->pb, buf, sizeof(buf));
 161     return 0;
 162 }
 163
 164 static int kvag_write_trailer(AVFormatContext *s)
 165 {
 166     int64_t file_size, data_size;
 167
 168     file_size = avio_tell(s->pb);
 169     data_size = file_size - KVAG_HEADER_SIZE;
 170     if (data_size < UINT32_MAX) {
 171         avio_seek(s->pb, 4, SEEK_SET);
 172         avio_wl32(s->pb, (uint32_t)data_size);
 173         avio_seek(s->pb, file_size, SEEK_SET);
 174     } else {
 175         av_log(s, AV_LOG_WARNING,
 176                "Filesize %"PRId64" invalid for KVAG, output file will be broken\n",
 177                file_size);
 178     }
 179
 180     return 0;
 181 }
 182
 183 const FFOutputFormat ff_kvag_muxer = {
 184     .p.name         = "kvag",
 185     .p.long_name    = NULL_IF_CONFIG_SMALL("Simon & Schuster Interactive VAG"),
 186     .p.extensions   = "vag",
 187     .p.audio_codec  = AV_CODEC_ID_ADPCM_IMA_SSI,
 188     .p.video_codec  = AV_CODEC_ID_NONE,
 189     .p.subtitle_codec = AV_CODEC_ID_NONE,
 190     .flags_internal   = FF_OFMT_FLAG_MAX_ONE_OF_EACH |
 191                         FF_OFMT_FLAG_ONLY_DEFAULT_CODECS,
 192     .init           = kvag_write_init,
 193     .write_header   = kvag_write_header,
 194     .write_packet   = ff_raw_write_packet,
 195     .write_trailer  = kvag_write_trailer
 196 };
 197 #endif