libavformat/rl2.c

   1 /*
   2  * RL2 Format Demuxer
   3  * Copyright (c) 2008 Sascha Sommer (saschasommer@freenet.de)
   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 /**
  23  * RL2 file demuxer
  24  * @file libavformat/rl2.c
  25  * @author Sascha Sommer (saschasommer@freenet.de)
  26  * For more information regarding the RL2 file format, visit:
  27  *   http://wiki.multimedia.cx/index.php?title=RL2
  28  *
  29  * extradata:
  30  * 2 byte le initial drawing offset within 320x200 viewport
  31  * 4 byte le number of used colors
  32  * 256 * 3 bytes rgb palette
  33  * optional background_frame
  34  */
  35
  36 #include "libavutil/intreadwrite.h"
  37 #include "avformat.h"
  38
  39 #define EXTRADATA1_SIZE (6 + 256 * 3) ///< video base, clr, palette
  40
  41 #define FORM_TAG MKBETAG('F', 'O', 'R', 'M')
  42 #define RLV2_TAG MKBETAG('R', 'L', 'V', '2')
  43 #define RLV3_TAG MKBETAG('R', 'L', 'V', '3')
  44
  45 typedef struct Rl2DemuxContext {
  46     unsigned int index_pos[2];   ///< indexes in the sample tables
  47 } Rl2DemuxContext;
  48
  49
  50 /**
  51  * check if the file is in rl2 format
  52  * @param p probe buffer
  53  * @return 0 when the probe buffer does not contain rl2 data, > 0 otherwise
  54  */
  55 static int rl2_probe(AVProbeData *p)
  56 {
  57
  58     if(AV_RB32(&p->buf[0]) != FORM_TAG)
  59         return 0;
  60
  61     if(AV_RB32(&p->buf[8]) != RLV2_TAG &&
  62         AV_RB32(&p->buf[8]) != RLV3_TAG)
  63         return 0;
  64
  65     return AVPROBE_SCORE_MAX;
  66 }
  67
  68 /**
  69  * read rl2 header data and setup the avstreams
  70  * @param s demuxer context
  71  * @param ap format parameters
  72  * @return 0 on success, AVERROR otherwise
  73  */
  74 static av_cold int rl2_read_header(AVFormatContext *s,
  75                             AVFormatParameters *ap)
  76 {
  77     ByteIOContext *pb = s->pb;
  78     AVStream *st;
  79     unsigned int frame_count;
  80     unsigned int audio_frame_counter = 0;
  81     unsigned int video_frame_counter = 0;
  82     unsigned int back_size;
  83     int data_size;
  84     unsigned short encoding_method;
  85     unsigned short sound_rate;
  86     unsigned short rate;
  87     unsigned short channels;
  88     unsigned short def_sound_size;
  89     unsigned int signature;
  90     unsigned int pts_den = 11025; /* video only case */
  91     unsigned int pts_num = 1103;
  92     unsigned int* chunk_offset = NULL;
  93     int* chunk_size = NULL;
  94     int* audio_size = NULL;
  95     int i;
  96     int ret = 0;
  97
  98     url_fskip(pb,4);          /* skip FORM tag */
  99     back_size = get_le32(pb); /** get size of the background frame */
 100     signature = get_be32(pb);
 101     data_size = get_be32(pb);
 102     frame_count = get_le32(pb);
 103
 104     /* disallow back_sizes and frame_counts that may lead to overflows later */
 105     if(back_size > INT_MAX/2  || frame_count > INT_MAX / sizeof(uint32_t))
 106         return AVERROR_INVALIDDATA;
 107
 108     encoding_method = get_le16(pb);
 109     sound_rate = get_le16(pb);
 110     rate = get_le16(pb);
 111     channels = get_le16(pb);
 112     def_sound_size = get_le16(pb);
 113
 114     /** setup video stream */
 115     st = av_new_stream(s, 0);
 116     if(!st)
 117          return AVERROR(ENOMEM);
 118
 119     st->codec->codec_type = CODEC_TYPE_VIDEO;
 120     st->codec->codec_id = CODEC_ID_RL2;
 121     st->codec->codec_tag = 0;  /* no fourcc */
 122     st->codec->width = 320;
 123     st->codec->height = 200;
 124
 125     /** allocate and fill extradata */
 126     st->codec->extradata_size = EXTRADATA1_SIZE;
 127
 128     if(signature == RLV3_TAG && back_size > 0)
 129         st->codec->extradata_size += back_size;
 130
 131     st->codec->extradata = av_mallocz(st->codec->extradata_size +
 132                                           FF_INPUT_BUFFER_PADDING_SIZE);
 133     if(!st->codec->extradata)
 134         return AVERROR(ENOMEM);
 135
 136     if(get_buffer(pb,st->codec->extradata,st->codec->extradata_size) !=
 137                       st->codec->extradata_size)
 138         return AVERROR(EIO);
 139
 140     /** setup audio stream if present */
 141     if(sound_rate){
 142         pts_num = def_sound_size;
 143         pts_den = rate;
 144
 145         st = av_new_stream(s, 0);
 146         if (!st)
 147             return AVERROR(ENOMEM);
 148         st->codec->codec_type = CODEC_TYPE_AUDIO;
 149         st->codec->codec_id = CODEC_ID_PCM_U8;
 150         st->codec->codec_tag = 1;
 151         st->codec->channels = channels;
 152         st->codec->bits_per_coded_sample = 8;
 153         st->codec->sample_rate = rate;
 154         st->codec->bit_rate = st->codec->channels * st->codec->sample_rate *
 155             st->codec->bits_per_coded_sample;
 156         st->codec->block_align = st->codec->channels *
 157             st->codec->bits_per_coded_sample / 8;
 158         av_set_pts_info(st,32,1,rate);
 159     }
 160
 161     av_set_pts_info(s->streams[0], 32, pts_num, pts_den);
 162
 163     chunk_size =   av_malloc(frame_count * sizeof(uint32_t));
 164     audio_size =   av_malloc(frame_count * sizeof(uint32_t));
 165     chunk_offset = av_malloc(frame_count * sizeof(uint32_t));
 166
 167     if(!chunk_size || !audio_size || !chunk_offset){
 168         av_free(chunk_size);
 169         av_free(audio_size);
 170         av_free(chunk_offset);
 171         return AVERROR(ENOMEM);
 172     }
 173
 174     /** read offset and size tables */
 175     for(i=0; i < frame_count;i++)
 176         chunk_size[i] = get_le32(pb);
 177     for(i=0; i < frame_count;i++)
 178         chunk_offset[i] = get_le32(pb);
 179     for(i=0; i < frame_count;i++)
 180         audio_size[i] = get_le32(pb) & 0xFFFF;
 181
 182     /** build the sample index */
 183     for(i=0;i<frame_count;i++){
 184         if(chunk_size[i] < 0 || audio_size[i] > chunk_size[i]){
 185             ret = AVERROR_INVALIDDATA;
 186             break;
 187         }
 188
 189         if(sound_rate && audio_size[i]){
 190             av_add_index_entry(s->streams[1], chunk_offset[i],
 191                 audio_frame_counter,audio_size[i], 0, AVINDEX_KEYFRAME);
 192             audio_frame_counter += audio_size[i] / channels;
 193         }
 194         av_add_index_entry(s->streams[0], chunk_offset[i] + audio_size[i],
 195             video_frame_counter,chunk_size[i]-audio_size[i],0,AVINDEX_KEYFRAME);
 196         ++video_frame_counter;
 197     }
 198
 199
 200     av_free(chunk_size);
 201     av_free(audio_size);
 202     av_free(chunk_offset);
 203
 204     return ret;
 205 }
 206
 207 /**
 208  * read a single audio or video packet
 209  * @param s demuxer context
 210  * @param pkt the packet to be filled
 211  * @return 0 on success, AVERROR otherwise
 212  */
 213 static int rl2_read_packet(AVFormatContext *s,
 214                             AVPacket *pkt)
 215 {
 216     Rl2DemuxContext *rl2 = s->priv_data;
 217     ByteIOContext *pb = s->pb;
 218     AVIndexEntry *sample = NULL;
 219     int i;
 220     int ret = 0;
 221     int stream_id = -1;
 222     int64_t pos = INT64_MAX;
 223
 224     /** check if there is a valid video or audio entry that can be used */
 225     for(i=0; i<s->nb_streams; i++){
 226         if(rl2->index_pos[i] < s->streams[i]->nb_index_entries
 227               && s->streams[i]->index_entries[ rl2->index_pos[i] ].pos < pos){
 228             sample = &s->streams[i]->index_entries[ rl2->index_pos[i] ];
 229             pos= sample->pos;
 230             stream_id= i;
 231         }
 232     }
 233
 234     if(stream_id == -1)
 235         return AVERROR(EIO);
 236
 237     ++rl2->index_pos[stream_id];
 238
 239     /** position the stream (will probably be there anyway) */
 240     url_fseek(pb, sample->pos, SEEK_SET);
 241
 242     /** fill the packet */
 243     ret = av_get_packet(pb, pkt, sample->size);
 244     if(ret != sample->size){
 245         av_free_packet(pkt);
 246         return AVERROR(EIO);
 247     }
 248
 249     pkt->stream_index = stream_id;
 250     pkt->pts = sample->timestamp;
 251
 252     return ret;
 253 }
 254
 255 /**
 256  * seek to a new timestamp
 257  * @param s demuxer context
 258  * @param stream_index index of the stream that should be seeked
 259  * @param timestamp wanted timestamp
 260  * @param flags direction and seeking mode
 261  * @return 0 on success, -1 otherwise
 262  */
 263 static int rl2_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
 264 {
 265     AVStream *st = s->streams[stream_index];
 266     Rl2DemuxContext *rl2 = s->priv_data;
 267     int i;
 268     int index = av_index_search_timestamp(st, timestamp, flags);
 269     if(index < 0)
 270         return -1;
 271
 272     rl2->index_pos[stream_index] = index;
 273     timestamp = st->index_entries[index].timestamp;
 274
 275     for(i=0; i < s->nb_streams; i++){
 276         AVStream *st2 = s->streams[i];
 277         index = av_index_search_timestamp(st2,
 278                     av_rescale_q(timestamp, st->time_base, st2->time_base),
 279                     flags | AVSEEK_FLAG_BACKWARD);
 280
 281         if(index < 0)
 282             index = 0;
 283
 284         rl2->index_pos[i] = index;
 285     }
 286
 287     return 0;
 288 }
 289
 290 AVInputFormat rl2_demuxer = {
 291     "rl2",
 292     NULL_IF_CONFIG_SMALL("RL2 format"),
 293     sizeof(Rl2DemuxContext),
 294     rl2_probe,
 295     rl2_read_header,
 296     rl2_read_packet,
 297     NULL,
 298     rl2_read_seek,
 299 };
 300