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libavformat/bethsoftvid.c

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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 "libavcodec/bethsoftvideo.h"
00033 
00034 typedef struct BVID_DemuxContext
00035 {
00036     int nframes;
00040     int bethsoft_global_delay;
00041 
00044     int video_pts;
00045 
00046     int is_finished;
00047 
00048 } BVID_DemuxContext;
00049 
00050 static int vid_probe(AVProbeData *p)
00051 {
00052     // little endian VID tag, file starts with "VID\0"
00053     if (AV_RL32(p->buf) != MKTAG('V', 'I', 'D', 0))
00054         return 0;
00055 
00056     return AVPROBE_SCORE_MAX;
00057 }
00058 
00059 static int vid_read_header(AVFormatContext *s,
00060                             AVFormatParameters *ap)
00061 {
00062     BVID_DemuxContext *vid = s->priv_data;
00063     ByteIOContext *pb = s->pb;
00064     AVStream *stream;
00065 
00066     /* load main header. Contents:
00067     *    bytes: 'V' 'I' 'D'
00068     *    int16s: always_512, nframes, width, height, delay, always_14
00069     */
00070     url_fseek(pb, 5, SEEK_CUR);
00071     vid->nframes = get_le16(pb);
00072 
00073     stream = av_new_stream(s, 0);
00074     if (!stream)
00075         return AVERROR(ENOMEM);
00076     av_set_pts_info(stream, 32, 1, 60);     // 16 ms increments, i.e. 60 fps
00077     stream->codec->codec_type = AVMEDIA_TYPE_VIDEO;
00078     stream->codec->codec_id = CODEC_ID_BETHSOFTVID;
00079     stream->codec->width = get_le16(pb);
00080     stream->codec->height = get_le16(pb);
00081     stream->codec->pix_fmt = PIX_FMT_PAL8;
00082     vid->bethsoft_global_delay = get_le16(pb);
00083     get_le16(pb);
00084 
00085     // done with video codec, set up audio codec
00086     stream = av_new_stream(s, 0);
00087     if (!stream)
00088         return AVERROR(ENOMEM);
00089     stream->codec->codec_type = AVMEDIA_TYPE_AUDIO;
00090     stream->codec->codec_id = CODEC_ID_PCM_U8;
00091     stream->codec->channels = 1;
00092     stream->codec->sample_rate = 11025;
00093     stream->codec->bits_per_coded_sample = 8;
00094     stream->codec->bit_rate = stream->codec->channels * stream->codec->sample_rate * stream->codec->bits_per_coded_sample;
00095 
00096     return 0;
00097 }
00098 
00099 #define BUFFER_PADDING_SIZE 1000
00100 static int read_frame(BVID_DemuxContext *vid, ByteIOContext *pb, AVPacket *pkt,
00101                       uint8_t block_type, AVFormatContext *s, int npixels)
00102 {
00103     uint8_t * vidbuf_start = NULL;
00104     int vidbuf_nbytes = 0;
00105     int code;
00106     int bytes_copied = 0;
00107     int position;
00108     unsigned int vidbuf_capacity;
00109 
00110     vidbuf_start = av_malloc(vidbuf_capacity = BUFFER_PADDING_SIZE);
00111     if(!vidbuf_start)
00112         return AVERROR(ENOMEM);
00113 
00114     // save the file position for the packet, include block type
00115     position = url_ftell(pb) - 1;
00116 
00117     vidbuf_start[vidbuf_nbytes++] = block_type;
00118 
00119     // get the video delay (next int16), and set the presentation time
00120     vid->video_pts += vid->bethsoft_global_delay + get_le16(pb);
00121 
00122     // set the y offset if it exists (decoder header data should be in data section)
00123     if(block_type == VIDEO_YOFF_P_FRAME){
00124         if(get_buffer(pb, &vidbuf_start[vidbuf_nbytes], 2) != 2)
00125             goto fail;
00126         vidbuf_nbytes += 2;
00127     }
00128 
00129     do{
00130         vidbuf_start = av_fast_realloc(vidbuf_start, &vidbuf_capacity, vidbuf_nbytes + BUFFER_PADDING_SIZE);
00131         if(!vidbuf_start)
00132             return AVERROR(ENOMEM);
00133 
00134         code = get_byte(pb);
00135         vidbuf_start[vidbuf_nbytes++] = code;
00136 
00137         if(code >= 0x80){ // rle sequence
00138             if(block_type == VIDEO_I_FRAME)
00139                 vidbuf_start[vidbuf_nbytes++] = get_byte(pb);
00140         } else if(code){ // plain sequence
00141             if(get_buffer(pb, &vidbuf_start[vidbuf_nbytes], code) != code)
00142                 goto fail;
00143             vidbuf_nbytes += code;
00144         }
00145         bytes_copied += code & 0x7F;
00146         if(bytes_copied == npixels){ // sometimes no stop character is given, need to keep track of bytes copied
00147             // may contain a 0 byte even if read all pixels
00148             if(get_byte(pb))
00149                 url_fseek(pb, -1, SEEK_CUR);
00150             break;
00151         }
00152         if(bytes_copied > npixels)
00153             goto fail;
00154     } while(code);
00155 
00156     // copy data into packet
00157     if(av_new_packet(pkt, vidbuf_nbytes) < 0)
00158         goto fail;
00159     memcpy(pkt->data, vidbuf_start, vidbuf_nbytes);
00160     av_free(vidbuf_start);
00161 
00162     pkt->pos = position;
00163     pkt->stream_index = 0;  // use the video decoder, which was initialized as the first stream
00164     pkt->pts = vid->video_pts;
00165 
00166     vid->nframes--;  // used to check if all the frames were read
00167     return vidbuf_nbytes;
00168 fail:
00169     av_free(vidbuf_start);
00170     return -1;
00171 }
00172 
00173 static int vid_read_packet(AVFormatContext *s,
00174                            AVPacket *pkt)
00175 {
00176     BVID_DemuxContext *vid = s->priv_data;
00177     ByteIOContext *pb = s->pb;
00178     unsigned char block_type;
00179     int audio_length;
00180     int ret_value;
00181 
00182     if(vid->is_finished || url_feof(pb))
00183         return AVERROR(EIO);
00184 
00185     block_type = get_byte(pb);
00186     switch(block_type){
00187         case PALETTE_BLOCK:
00188             url_fseek(pb, -1, SEEK_CUR);     // include block type
00189             ret_value = av_get_packet(pb, pkt, 3 * 256 + 1);
00190             if(ret_value != 3 * 256 + 1){
00191                 av_free_packet(pkt);
00192                 return AVERROR(EIO);
00193             }
00194             pkt->stream_index = 0;
00195             return ret_value;
00196 
00197         case FIRST_AUDIO_BLOCK:
00198             get_le16(pb);
00199             // soundblaster DAC used for sample rate, as on specification page (link above)
00200             s->streams[1]->codec->sample_rate = 1000000 / (256 - get_byte(pb));
00201             s->streams[1]->codec->bit_rate = s->streams[1]->codec->channels * s->streams[1]->codec->sample_rate * s->streams[1]->codec->bits_per_coded_sample;
00202         case AUDIO_BLOCK:
00203             audio_length = get_le16(pb);
00204             ret_value = av_get_packet(pb, pkt, audio_length);
00205             pkt->stream_index = 1;
00206             return ret_value != audio_length ? AVERROR(EIO) : ret_value;
00207 
00208         case VIDEO_P_FRAME:
00209         case VIDEO_YOFF_P_FRAME:
00210         case VIDEO_I_FRAME:
00211             return read_frame(vid, pb, pkt, block_type, s,
00212                               s->streams[0]->codec->width * s->streams[0]->codec->height);
00213 
00214         case EOF_BLOCK:
00215             if(vid->nframes != 0)
00216                 av_log(s, AV_LOG_VERBOSE, "reached terminating character but not all frames read.\n");
00217             vid->is_finished = 1;
00218             return AVERROR(EIO);
00219         default:
00220             av_log(s, AV_LOG_ERROR, "unknown block (character = %c, decimal = %d, hex = %x)!!!\n",
00221                    block_type, block_type, block_type); return -1;
00222     }
00223 
00224     return 0;
00225 }
00226 
00227 AVInputFormat bethsoftvid_demuxer = {
00228     "bethsoftvid",
00229     NULL_IF_CONFIG_SMALL("Bethesda Softworks VID format"),
00230     sizeof(BVID_DemuxContext),
00231     vid_probe,
00232     vid_read_header,
00233     vid_read_packet,
00234 };

Generated on Fri Sep 16 2011 17:17:48 for FFmpeg by  doxygen 1.7.1