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