FFmpeg: libavformat/bethsoftvid.c Source File

00001 /*
00002  * Bethsoft VID format Demuxer
00003  * Copyright (c) 2007 Nicholas Tung
00004  *
00005  * This file is part of FFmpeg.
00006  *
00007  * FFmpeg is free software; you can redistribute it and/or
00008  * modify it under the terms of the GNU Lesser General Public
00009  * License as published by the Free Software Foundation; either
00010  * version 2.1 of the License, or (at your option) any later version.
00011  *
00012  * FFmpeg is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015  * Lesser General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU Lesser General Public
00018  * License along with FFmpeg; if not, write to the Free Software
00019  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00020  */
00021 
00030 #include "libavutil/intreadwrite.h"
00031 #include "avformat.h"
00032 #include "internal.h"
00033 #include "libavcodec/bethsoftvideo.h"
00034 
00035 #define BVID_PALETTE_SIZE 3 * 256
00036 
00037 #define DEFAULT_SAMPLE_RATE 11111
00038 
00039 typedef struct BVID_DemuxContext
00040 {
00041     int nframes;
00042     int sample_rate;        
00043     int width;              
00044     int height;             
00048     int bethsoft_global_delay;
00049     int video_index;        
00050     int audio_index;        
00051     uint8_t *palette;
00052 
00053     int is_finished;
00054 
00055 } BVID_DemuxContext;
00056 
00057 static int vid_probe(AVProbeData *p)
00058 {
00059     // little endian VID tag, file starts with "VID\0"
00060     if (AV_RL32(p->buf) != MKTAG('V', 'I', 'D', 0))
00061         return 0;
00062 
00063     return AVPROBE_SCORE_MAX;
00064 }
00065 
00066 static int vid_read_header(AVFormatContext *s)
00067 {
00068     BVID_DemuxContext *vid = s->priv_data;
00069     AVIOContext *pb = s->pb;
00070 
00071     /* load main header. Contents:
00072     *    bytes: 'V' 'I' 'D'
00073     *    int16s: always_512, nframes, width, height, delay, always_14
00074     */
00075     avio_skip(pb, 5);
00076     vid->nframes = avio_rl16(pb);
00077     vid->width   = avio_rl16(pb);
00078     vid->height  = avio_rl16(pb);
00079     vid->bethsoft_global_delay = avio_rl16(pb);
00080     avio_rl16(pb);
00081 
00082     // wait until the first packet to create each stream
00083     vid->video_index = -1;
00084     vid->audio_index = -1;
00085     vid->sample_rate = DEFAULT_SAMPLE_RATE;
00086     s->ctx_flags |= AVFMTCTX_NOHEADER;
00087 
00088     return 0;
00089 }
00090 
00091 #define BUFFER_PADDING_SIZE 1000
00092 static int read_frame(BVID_DemuxContext *vid, AVIOContext *pb, AVPacket *pkt,
00093                       uint8_t block_type, AVFormatContext *s)
00094 {
00095     uint8_t * vidbuf_start = NULL;
00096     int vidbuf_nbytes = 0;
00097     int code;
00098     int bytes_copied = 0;
00099     int position, duration, npixels;
00100     unsigned int vidbuf_capacity;
00101     int ret = 0;
00102     AVStream *st;
00103 
00104     if (vid->video_index < 0) {
00105         st = avformat_new_stream(s, NULL);
00106         if (!st)
00107             return AVERROR(ENOMEM);
00108         vid->video_index = st->index;
00109         if (vid->audio_index < 0) {
00110             av_log_ask_for_sample(s, "No audio packet before first video "
00111                                   "packet. Using default video time base.\n");
00112         }
00113         avpriv_set_pts_info(st, 64, 185, vid->sample_rate);
00114         st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
00115         st->codec->codec_id   = AV_CODEC_ID_BETHSOFTVID;
00116         st->codec->width      = vid->width;
00117         st->codec->height     = vid->height;
00118     }
00119     st      = s->streams[vid->video_index];
00120     npixels = st->codec->width * st->codec->height;
00121 
00122     vidbuf_start = av_malloc(vidbuf_capacity = BUFFER_PADDING_SIZE);
00123     if(!vidbuf_start)
00124         return AVERROR(ENOMEM);
00125 
00126     // save the file position for the packet, include block type
00127     position = avio_tell(pb) - 1;
00128 
00129     vidbuf_start[vidbuf_nbytes++] = block_type;
00130 
00131     // get the current packet duration
00132     duration = vid->bethsoft_global_delay + avio_rl16(pb);
00133 
00134     // set the y offset if it exists (decoder header data should be in data section)
00135     if(block_type == VIDEO_YOFF_P_FRAME){
00136         if (avio_read(pb, &vidbuf_start[vidbuf_nbytes], 2) != 2) {
00137             ret = AVERROR(EIO);
00138             goto fail;
00139         }
00140         vidbuf_nbytes += 2;
00141     }
00142 
00143     do{
00144         vidbuf_start = av_fast_realloc(vidbuf_start, &vidbuf_capacity, vidbuf_nbytes + BUFFER_PADDING_SIZE);
00145         if(!vidbuf_start)
00146             return AVERROR(ENOMEM);
00147 
00148         code = avio_r8(pb);
00149         vidbuf_start[vidbuf_nbytes++] = code;
00150 
00151         if(code >= 0x80){ // rle sequence
00152             if(block_type == VIDEO_I_FRAME)
00153                 vidbuf_start[vidbuf_nbytes++] = avio_r8(pb);
00154         } else if(code){ // plain sequence
00155             if (avio_read(pb, &vidbuf_start[vidbuf_nbytes], code) != code) {
00156                 ret = AVERROR(EIO);
00157                 goto fail;
00158             }
00159             vidbuf_nbytes += code;
00160         }
00161         bytes_copied += code & 0x7F;
00162         if(bytes_copied == npixels){ // sometimes no stop character is given, need to keep track of bytes copied
00163             // may contain a 0 byte even if read all pixels
00164             if(avio_r8(pb))
00165                 avio_seek(pb, -1, SEEK_CUR);
00166             break;
00167         }
00168         if (bytes_copied > npixels) {
00169             ret = AVERROR_INVALIDDATA;
00170             goto fail;
00171         }
00172     } while(code);
00173 
00174     // copy data into packet
00175     if ((ret = av_new_packet(pkt, vidbuf_nbytes)) < 0)
00176         goto fail;
00177     memcpy(pkt->data, vidbuf_start, vidbuf_nbytes);
00178     av_free(vidbuf_start);
00179 
00180     pkt->pos = position;
00181     pkt->stream_index = vid->video_index;
00182     pkt->duration = duration;
00183     if (block_type == VIDEO_I_FRAME)
00184         pkt->flags |= AV_PKT_FLAG_KEY;
00185 
00186     /* if there is a new palette available, add it to packet side data */
00187     if (vid->palette) {
00188         uint8_t *pdata = av_packet_new_side_data(pkt, AV_PKT_DATA_PALETTE,
00189                                                  BVID_PALETTE_SIZE);
00190         memcpy(pdata, vid->palette, BVID_PALETTE_SIZE);
00191         av_freep(&vid->palette);
00192     }
00193 
00194     vid->nframes--;  // used to check if all the frames were read
00195     return 0;
00196 fail:
00197     av_free(vidbuf_start);
00198     return ret;
00199 }
00200 
00201 static int vid_read_packet(AVFormatContext *s,
00202                            AVPacket *pkt)
00203 {
00204     BVID_DemuxContext *vid = s->priv_data;
00205     AVIOContext *pb = s->pb;
00206     unsigned char block_type;
00207     int audio_length;
00208     int ret_value;
00209 
00210     if(vid->is_finished || url_feof(pb))
00211         return AVERROR(EIO);
00212 
00213     block_type = avio_r8(pb);
00214     switch(block_type){
00215         case PALETTE_BLOCK:
00216             if (vid->palette) {
00217                 av_log(s, AV_LOG_WARNING, "discarding unused palette\n");
00218                 av_freep(&vid->palette);
00219             }
00220             vid->palette = av_malloc(BVID_PALETTE_SIZE);
00221             if (!vid->palette)
00222                 return AVERROR(ENOMEM);
00223             if (avio_read(pb, vid->palette, BVID_PALETTE_SIZE) != BVID_PALETTE_SIZE) {
00224                 av_freep(&vid->palette);
00225                 return AVERROR(EIO);
00226             }
00227             return vid_read_packet(s, pkt);
00228 
00229         case FIRST_AUDIO_BLOCK:
00230             avio_rl16(pb);
00231             // soundblaster DAC used for sample rate, as on specification page (link above)
00232             vid->sample_rate = 1000000 / (256 - avio_r8(pb));
00233         case AUDIO_BLOCK:
00234             if (vid->audio_index < 0) {
00235                 AVStream *st = avformat_new_stream(s, NULL);
00236                 if (!st)
00237                     return AVERROR(ENOMEM);
00238                 vid->audio_index                 = st->index;
00239                 st->codec->codec_type            = AVMEDIA_TYPE_AUDIO;
00240                 st->codec->codec_id              = AV_CODEC_ID_PCM_U8;
00241                 st->codec->channels              = 1;
00242                 st->codec->bits_per_coded_sample = 8;
00243                 st->codec->sample_rate           = vid->sample_rate;
00244                 st->codec->bit_rate              = 8 * st->codec->sample_rate;
00245                 st->start_time                   = 0;
00246                 avpriv_set_pts_info(st, 64, 1, vid->sample_rate);
00247             }
00248             audio_length = avio_rl16(pb);
00249             if ((ret_value = av_get_packet(pb, pkt, audio_length)) != audio_length) {
00250                 if (ret_value < 0)
00251                     return ret_value;
00252                 av_log(s, AV_LOG_ERROR, "incomplete audio block\n");
00253                 return AVERROR(EIO);
00254             }
00255             pkt->stream_index = vid->audio_index;
00256             pkt->duration     = audio_length;
00257             pkt->flags |= AV_PKT_FLAG_KEY;
00258             return 0;
00259 
00260         case VIDEO_P_FRAME:
00261         case VIDEO_YOFF_P_FRAME:
00262         case VIDEO_I_FRAME:
00263             return read_frame(vid, pb, pkt, block_type, s);
00264 
00265         case EOF_BLOCK:
00266             if(vid->nframes != 0)
00267                 av_log(s, AV_LOG_VERBOSE, "reached terminating character but not all frames read.\n");
00268             vid->is_finished = 1;
00269             return AVERROR(EIO);
00270         default:
00271             av_log(s, AV_LOG_ERROR, "unknown block (character = %c, decimal = %d, hex = %x)!!!\n",
00272                    block_type, block_type, block_type);
00273             return AVERROR_INVALIDDATA;
00274     }
00275 }
00276 
00277 static int vid_read_close(AVFormatContext *s)
00278 {
00279     BVID_DemuxContext *vid = s->priv_data;
00280     av_freep(&vid->palette);
00281     return 0;
00282 }
00283 
00284 AVInputFormat ff_bethsoftvid_demuxer = {
00285     .name           = "bethsoftvid",
00286     .long_name      = NULL_IF_CONFIG_SMALL("Bethesda Softworks VID"),
00287     .priv_data_size = sizeof(BVID_DemuxContext),
00288     .read_probe     = vid_probe,
00289     .read_header    = vid_read_header,
00290     .read_packet    = vid_read_packet,
00291     .read_close     = vid_read_close,
00292 };