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libavformat/oggparsetheora.c

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00001 
00025 #include <stdlib.h>
00026 #include "libavutil/bswap.h"
00027 #include "libavcodec/bitstream.h"
00028 #include "avformat.h"
00029 #include "oggdec.h"
00030 
00031 struct theora_params {
00032     int gpshift;
00033     int gpmask;
00034     unsigned version;
00035 };
00036 
00037 static int
00038 theora_header (AVFormatContext * s, int idx)
00039 {
00040     struct ogg *ogg = s->priv_data;
00041     struct ogg_stream *os = ogg->streams + idx;
00042     AVStream *st = s->streams[idx];
00043     struct theora_params *thp = os->private;
00044     int cds = st->codec->extradata_size + os->psize + 2;
00045     uint8_t *cdp;
00046 
00047     if(!(os->buf[os->pstart] & 0x80))
00048         return 0;
00049 
00050     if(!thp){
00051         thp = av_mallocz(sizeof(*thp));
00052         os->private = thp;
00053     }
00054 
00055     if (os->buf[os->pstart] == 0x80) {
00056         GetBitContext gb;
00057         int width, height;
00058 
00059         init_get_bits(&gb, os->buf + os->pstart, os->psize*8);
00060 
00061         skip_bits(&gb, 7*8); /* 0x80"theora" */
00062 
00063         thp->version = get_bits_long(&gb, 24);
00064         if (thp->version < 0x030100)
00065         {
00066             av_log(s, AV_LOG_ERROR,
00067                 "Too old or unsupported Theora (%x)\n", thp->version);
00068             return -1;
00069         }
00070 
00071         width  = get_bits(&gb, 16) << 4;
00072         height = get_bits(&gb, 16) << 4;
00073         avcodec_set_dimensions(st->codec, width, height);
00074 
00075         if (thp->version >= 0x030400)
00076             skip_bits(&gb, 100);
00077 
00078         if (thp->version >= 0x030200) {
00079             width  = get_bits_long(&gb, 24);
00080             height = get_bits_long(&gb, 24);
00081             if (   width  <= st->codec->width  && width  > st->codec->width-16
00082                 && height <= st->codec->height && height > st->codec->height-16)
00083                 avcodec_set_dimensions(st->codec, width, height);
00084 
00085             skip_bits(&gb, 16);
00086         }
00087         st->codec->time_base.den = get_bits_long(&gb, 32);
00088         st->codec->time_base.num = get_bits_long(&gb, 32);
00089         st->time_base = st->codec->time_base;
00090 
00091         st->sample_aspect_ratio.num = get_bits_long(&gb, 24);
00092         st->sample_aspect_ratio.den = get_bits_long(&gb, 24);
00093 
00094         if (thp->version >= 0x030200)
00095             skip_bits(&gb, 38);
00096         if (thp->version >= 0x304000)
00097             skip_bits(&gb, 2);
00098 
00099         thp->gpshift = get_bits(&gb, 5);
00100         thp->gpmask = (1 << thp->gpshift) - 1;
00101 
00102         st->codec->codec_type = CODEC_TYPE_VIDEO;
00103         st->codec->codec_id = CODEC_ID_THEORA;
00104 
00105     } else if (os->buf[os->pstart] == 0x83) {
00106         vorbis_comment (s, os->buf + os->pstart + 7, os->psize - 8);
00107     }
00108 
00109     st->codec->extradata = av_realloc (st->codec->extradata, cds);
00110     cdp = st->codec->extradata + st->codec->extradata_size;
00111     *cdp++ = os->psize >> 8;
00112     *cdp++ = os->psize & 0xff;
00113     memcpy (cdp, os->buf + os->pstart, os->psize);
00114     st->codec->extradata_size = cds;
00115 
00116     return 1;
00117 }
00118 
00119 static uint64_t
00120 theora_gptopts(AVFormatContext *ctx, int idx, uint64_t gp)
00121 {
00122     struct ogg *ogg = ctx->priv_data;
00123     struct ogg_stream *os = ogg->streams + idx;
00124     struct theora_params *thp = os->private;
00125     uint64_t iframe = gp >> thp->gpshift;
00126     uint64_t pframe = gp & thp->gpmask;
00127 
00128     if (thp->version < 0x030201)
00129         iframe++;
00130 
00131     if(!pframe)
00132         os->pflags |= PKT_FLAG_KEY;
00133 
00134     return iframe + pframe;
00135 }
00136 
00137 const struct ogg_codec ff_theora_codec = {
00138     .magic = "\200theora",
00139     .magicsize = 7,
00140     .header = theora_header,
00141     .gptopts = theora_gptopts
00142 };

Generated on Sat Feb 16 2013 09:23:15 for ffmpeg by  doxygen 1.7.1