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libavformat/idcin.c

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00001 /*
00002  * id Quake II CIN File Demuxer
00003  * Copyright (c) 2003 The ffmpeg Project
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 
00071 #include "libavutil/intreadwrite.h"
00072 #include "avformat.h"
00073 
00074 #define HUFFMAN_TABLE_SIZE (64 * 1024)
00075 #define IDCIN_FPS 14
00076 
00077 typedef struct IdcinDemuxContext {
00078     int video_stream_index;
00079     int audio_stream_index;
00080     int audio_chunk_size1;
00081     int audio_chunk_size2;
00082 
00083     /* demux state variables */
00084     int current_audio_chunk;
00085     int next_chunk_is_video;
00086     int audio_present;
00087 
00088     int64_t pts;
00089 
00090     AVPaletteControl palctrl;
00091 } IdcinDemuxContext;
00092 
00093 static int idcin_probe(AVProbeData *p)
00094 {
00095     unsigned int number;
00096 
00097     /*
00098      * This is what you could call a "probabilistic" file check: id CIN
00099      * files don't have a definite file signature. In lieu of such a marker,
00100      * perform sanity checks on the 5 32-bit header fields:
00101      *  width, height: greater than 0, less than or equal to 1024
00102      * audio sample rate: greater than or equal to 8000, less than or
00103      *  equal to 48000, or 0 for no audio
00104      * audio sample width (bytes/sample): 0 for no audio, or 1 or 2
00105      * audio channels: 0 for no audio, or 1 or 2
00106      */
00107 
00108     /* check we have enough data to do all checks, otherwise the
00109        0-padding may cause a wrong recognition */
00110     if (p->buf_size < 20)
00111         return 0;
00112 
00113     /* check the video width */
00114     number = AV_RL32(&p->buf[0]);
00115     if ((number == 0) || (number > 1024))
00116        return 0;
00117 
00118     /* check the video height */
00119     number = AV_RL32(&p->buf[4]);
00120     if ((number == 0) || (number > 1024))
00121        return 0;
00122 
00123     /* check the audio sample rate */
00124     number = AV_RL32(&p->buf[8]);
00125     if ((number != 0) && ((number < 8000) | (number > 48000)))
00126         return 0;
00127 
00128     /* check the audio bytes/sample */
00129     number = AV_RL32(&p->buf[12]);
00130     if (number > 2)
00131         return 0;
00132 
00133     /* check the audio channels */
00134     number = AV_RL32(&p->buf[16]);
00135     if (number > 2)
00136         return 0;
00137 
00138     /* return half certainly since this check is a bit sketchy */
00139     return AVPROBE_SCORE_MAX / 2;
00140 }
00141 
00142 static int idcin_read_header(AVFormatContext *s,
00143                              AVFormatParameters *ap)
00144 {
00145     ByteIOContext *pb = s->pb;
00146     IdcinDemuxContext *idcin = s->priv_data;
00147     AVStream *st;
00148     unsigned int width, height;
00149     unsigned int sample_rate, bytes_per_sample, channels;
00150 
00151     /* get the 5 header parameters */
00152     width = get_le32(pb);
00153     height = get_le32(pb);
00154     sample_rate = get_le32(pb);
00155     bytes_per_sample = get_le32(pb);
00156     channels = get_le32(pb);
00157 
00158     st = av_new_stream(s, 0);
00159     if (!st)
00160         return AVERROR(ENOMEM);
00161     av_set_pts_info(st, 33, 1, IDCIN_FPS);
00162     idcin->video_stream_index = st->index;
00163     st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
00164     st->codec->codec_id = CODEC_ID_IDCIN;
00165     st->codec->codec_tag = 0;  /* no fourcc */
00166     st->codec->width = width;
00167     st->codec->height = height;
00168 
00169     /* load up the Huffman tables into extradata */
00170     st->codec->extradata_size = HUFFMAN_TABLE_SIZE;
00171     st->codec->extradata = av_malloc(HUFFMAN_TABLE_SIZE);
00172     if (get_buffer(pb, st->codec->extradata, HUFFMAN_TABLE_SIZE) !=
00173         HUFFMAN_TABLE_SIZE)
00174         return AVERROR(EIO);
00175     /* save a reference in order to transport the palette */
00176     st->codec->palctrl = &idcin->palctrl;
00177 
00178     /* if sample rate is 0, assume no audio */
00179     if (sample_rate) {
00180         idcin->audio_present = 1;
00181         st = av_new_stream(s, 0);
00182         if (!st)
00183             return AVERROR(ENOMEM);
00184         av_set_pts_info(st, 33, 1, IDCIN_FPS);
00185         idcin->audio_stream_index = st->index;
00186         st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
00187         st->codec->codec_tag = 1;
00188         st->codec->channels = channels;
00189         st->codec->sample_rate = sample_rate;
00190         st->codec->bits_per_coded_sample = bytes_per_sample * 8;
00191         st->codec->bit_rate = sample_rate * bytes_per_sample * 8 * channels;
00192         st->codec->block_align = bytes_per_sample * channels;
00193         if (bytes_per_sample == 1)
00194             st->codec->codec_id = CODEC_ID_PCM_U8;
00195         else
00196             st->codec->codec_id = CODEC_ID_PCM_S16LE;
00197 
00198         if (sample_rate % 14 != 0) {
00199             idcin->audio_chunk_size1 = (sample_rate / 14) *
00200             bytes_per_sample * channels;
00201             idcin->audio_chunk_size2 = (sample_rate / 14 + 1) *
00202                 bytes_per_sample * channels;
00203         } else {
00204             idcin->audio_chunk_size1 = idcin->audio_chunk_size2 =
00205                 (sample_rate / 14) * bytes_per_sample * channels;
00206         }
00207         idcin->current_audio_chunk = 0;
00208     } else
00209         idcin->audio_present = 1;
00210 
00211     idcin->next_chunk_is_video = 1;
00212     idcin->pts = 0;
00213 
00214     return 0;
00215 }
00216 
00217 static int idcin_read_packet(AVFormatContext *s,
00218                              AVPacket *pkt)
00219 {
00220     int ret;
00221     unsigned int command;
00222     unsigned int chunk_size;
00223     IdcinDemuxContext *idcin = s->priv_data;
00224     ByteIOContext *pb = s->pb;
00225     int i;
00226     int palette_scale;
00227     unsigned char r, g, b;
00228     unsigned char palette_buffer[768];
00229 
00230     if (url_feof(s->pb))
00231         return AVERROR(EIO);
00232 
00233     if (idcin->next_chunk_is_video) {
00234         command = get_le32(pb);
00235         if (command == 2) {
00236             return AVERROR(EIO);
00237         } else if (command == 1) {
00238             /* trigger a palette change */
00239             idcin->palctrl.palette_changed = 1;
00240             if (get_buffer(pb, palette_buffer, 768) != 768)
00241                 return AVERROR(EIO);
00242             /* scale the palette as necessary */
00243             palette_scale = 2;
00244             for (i = 0; i < 768; i++)
00245                 if (palette_buffer[i] > 63) {
00246                     palette_scale = 0;
00247                     break;
00248                 }
00249 
00250             for (i = 0; i < 256; i++) {
00251                 r = palette_buffer[i * 3    ] << palette_scale;
00252                 g = palette_buffer[i * 3 + 1] << palette_scale;
00253                 b = palette_buffer[i * 3 + 2] << palette_scale;
00254                 idcin->palctrl.palette[i] = (r << 16) | (g << 8) | (b);
00255             }
00256         }
00257 
00258         chunk_size = get_le32(pb);
00259         /* skip the number of decoded bytes (always equal to width * height) */
00260         url_fseek(pb, 4, SEEK_CUR);
00261         chunk_size -= 4;
00262         ret= av_get_packet(pb, pkt, chunk_size);
00263         if (ret < 0)
00264             return ret;
00265         pkt->stream_index = idcin->video_stream_index;
00266         pkt->pts = idcin->pts;
00267     } else {
00268         /* send out the audio chunk */
00269         if (idcin->current_audio_chunk)
00270             chunk_size = idcin->audio_chunk_size2;
00271         else
00272             chunk_size = idcin->audio_chunk_size1;
00273         ret= av_get_packet(pb, pkt, chunk_size);
00274         if (ret < 0)
00275             return ret;
00276         pkt->stream_index = idcin->audio_stream_index;
00277         pkt->pts = idcin->pts;
00278 
00279         idcin->current_audio_chunk ^= 1;
00280         idcin->pts++;
00281     }
00282 
00283     if (idcin->audio_present)
00284         idcin->next_chunk_is_video ^= 1;
00285 
00286     return ret;
00287 }
00288 
00289 AVInputFormat idcin_demuxer = {
00290     "idcin",
00291     NULL_IF_CONFIG_SMALL("id Cinematic format"),
00292     sizeof(IdcinDemuxContext),
00293     idcin_probe,
00294     idcin_read_header,
00295     idcin_read_packet,
00296 };

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