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libavcodec/flvdec.c

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00001 /*
00002  * FLV decoding.
00003  * This file is part of FFmpeg.
00004  *
00005  * FFmpeg is free software; you can redistribute it and/or
00006  * modify it under the terms of the GNU Lesser General Public
00007  * License as published by the Free Software Foundation; either
00008  * version 2.1 of the License, or (at your option) any later version.
00009  *
00010  * FFmpeg is distributed in the hope that it will be useful,
00011  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00012  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00013  * Lesser General Public License for more details.
00014  *
00015  * You should have received a copy of the GNU Lesser General Public
00016  * License along with FFmpeg; if not, write to the Free Software
00017  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00018  */
00019 
00020 #include "mpegvideo.h"
00021 #include "h263.h"
00022 #include "flv.h"
00023 
00024 void ff_flv2_decode_ac_esc(GetBitContext *gb, int *level, int *run, int *last){
00025     int is11 = get_bits1(gb);
00026     *last = get_bits1(gb);
00027     *run = get_bits(gb, 6);
00028     if(is11){
00029         *level = get_sbits(gb, 11);
00030     } else {
00031         *level = get_sbits(gb, 7);
00032     }
00033 }
00034 
00035 int ff_flv_decode_picture_header(MpegEncContext *s)
00036 {
00037     int format, width, height;
00038 
00039     /* picture header */
00040     if (get_bits_long(&s->gb, 17) != 1) {
00041         av_log(s->avctx, AV_LOG_ERROR, "Bad picture start code\n");
00042         return -1;
00043     }
00044     format = get_bits(&s->gb, 5);
00045     if (format != 0 && format != 1) {
00046         av_log(s->avctx, AV_LOG_ERROR, "Bad picture format\n");
00047         return -1;
00048     }
00049     s->h263_flv = format+1;
00050     s->picture_number = get_bits(&s->gb, 8); /* picture timestamp */
00051     format = get_bits(&s->gb, 3);
00052     switch (format) {
00053     case 0:
00054         width = get_bits(&s->gb, 8);
00055         height = get_bits(&s->gb, 8);
00056         break;
00057     case 1:
00058         width = get_bits(&s->gb, 16);
00059         height = get_bits(&s->gb, 16);
00060         break;
00061     case 2:
00062         width = 352;
00063         height = 288;
00064         break;
00065     case 3:
00066         width = 176;
00067         height = 144;
00068         break;
00069     case 4:
00070         width = 128;
00071         height = 96;
00072         break;
00073     case 5:
00074         width = 320;
00075         height = 240;
00076         break;
00077     case 6:
00078         width = 160;
00079         height = 120;
00080         break;
00081     default:
00082         width = height = 0;
00083         break;
00084     }
00085     if(avcodec_check_dimensions(s->avctx, width, height))
00086         return -1;
00087     s->width = width;
00088     s->height = height;
00089 
00090     s->pict_type = FF_I_TYPE + get_bits(&s->gb, 2);
00091     s->dropable= s->pict_type > FF_P_TYPE;
00092     if (s->dropable)
00093         s->pict_type = FF_P_TYPE;
00094 
00095     skip_bits1(&s->gb); /* deblocking flag */
00096     s->chroma_qscale= s->qscale = get_bits(&s->gb, 5);
00097 
00098     s->h263_plus = 0;
00099 
00100     s->unrestricted_mv = 1;
00101     s->h263_long_vectors = 0;
00102 
00103     /* PEI */
00104     while (get_bits1(&s->gb) != 0) {
00105         skip_bits(&s->gb, 8);
00106     }
00107     s->f_code = 1;
00108 
00109     if(s->avctx->debug & FF_DEBUG_PICT_INFO){
00110         av_log(s->avctx, AV_LOG_DEBUG, "%c esc_type:%d, qp:%d num:%d\n",
00111                s->dropable ? 'D' : av_get_pict_type_char(s->pict_type), s->h263_flv-1, s->qscale, s->picture_number);
00112     }
00113 
00114     s->y_dc_scale_table=
00115     s->c_dc_scale_table= ff_mpeg1_dc_scale_table;
00116 
00117     return 0;
00118 }
00119 
00120 AVCodec flv_decoder = {
00121     "flv",
00122     AVMEDIA_TYPE_VIDEO,
00123     CODEC_ID_FLV1,
00124     sizeof(MpegEncContext),
00125     ff_h263_decode_init,
00126     NULL,
00127     ff_h263_decode_end,
00128     ff_h263_decode_frame,
00129     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1,
00130     .long_name= NULL_IF_CONFIG_SMALL("Flash Video (FLV) / Sorenson Spark / Sorenson H.263"),
00131     .pix_fmts= ff_pixfmt_list_420,
00132 };

Generated on Fri Sep 16 2011 17:17:36 for FFmpeg by  doxygen 1.7.1