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libavformat/oggparsetheora.c

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00001 
00025 #include <stdlib.h>
00026 #include "libavutil/bswap.h"
00027 #include "libavcodec/get_bits.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_long(&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         if (!(st->codec->time_base.num > 0 && st->codec->time_base.den > 0)) {
00090             av_log(s, AV_LOG_WARNING, "Invalid time base in theora stream, assuming 25 FPS\n");
00091             st->codec->time_base.num = 1;
00092             st->codec->time_base.den = 25;
00093         }
00094         st->time_base = st->codec->time_base;
00095 
00096         st->sample_aspect_ratio.num = get_bits_long(&gb, 24);
00097         st->sample_aspect_ratio.den = get_bits_long(&gb, 24);
00098 
00099         if (thp->version >= 0x030200)
00100             skip_bits_long(&gb, 38);
00101         if (thp->version >= 0x304000)
00102             skip_bits(&gb, 2);
00103 
00104         thp->gpshift = get_bits(&gb, 5);
00105         thp->gpmask = (1 << thp->gpshift) - 1;
00106 
00107         st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
00108         st->codec->codec_id = CODEC_ID_THEORA;
00109         st->need_parsing = AVSTREAM_PARSE_HEADERS;
00110 
00111     } else if (os->buf[os->pstart] == 0x83) {
00112         ff_vorbis_comment (s, &st->metadata, os->buf + os->pstart + 7, os->psize - 8);
00113     }
00114 
00115     st->codec->extradata = av_realloc (st->codec->extradata,
00116                                        cds + FF_INPUT_BUFFER_PADDING_SIZE);
00117     cdp = st->codec->extradata + st->codec->extradata_size;
00118     *cdp++ = os->psize >> 8;
00119     *cdp++ = os->psize & 0xff;
00120     memcpy (cdp, os->buf + os->pstart, os->psize);
00121     st->codec->extradata_size = cds;
00122 
00123     return 1;
00124 }
00125 
00126 static uint64_t
00127 theora_gptopts(AVFormatContext *ctx, int idx, uint64_t gp, int64_t *dts)
00128 {
00129     struct ogg *ogg = ctx->priv_data;
00130     struct ogg_stream *os = ogg->streams + idx;
00131     struct theora_params *thp = os->private;
00132     uint64_t iframe = gp >> thp->gpshift;
00133     uint64_t pframe = gp & thp->gpmask;
00134 
00135     if (thp->version < 0x030201)
00136         iframe++;
00137 
00138     if(!pframe)
00139         os->pflags |= AV_PKT_FLAG_KEY;
00140 
00141     if (dts)
00142         *dts = iframe + pframe;
00143 
00144     return iframe + pframe;
00145 }
00146 
00147 const struct ogg_codec ff_theora_codec = {
00148     .magic = "\200theora",
00149     .magicsize = 7,
00150     .header = theora_header,
00151     .gptopts = theora_gptopts
00152 };

Generated on Fri Sep 16 2011 17:17:50 for FFmpeg by  doxygen 1.7.1