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ffmpeg / libavcodec / flvdec.c @ 2912e87a

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/*
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 * FLV decoding.
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 * This file is part of Libav.
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 *
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 * Libav is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * Libav is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with Libav; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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#include "mpegvideo.h"
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#include "h263.h"
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#include "flv.h"
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#include "libavutil/imgutils.h"
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void ff_flv2_decode_ac_esc(GetBitContext *gb, int *level, int *run, int *last){
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    int is11 = get_bits1(gb);
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    *last = get_bits1(gb);
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    *run = get_bits(gb, 6);
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    if(is11){
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        *level = get_sbits(gb, 11);
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    } else {
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        *level = get_sbits(gb, 7);
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    }
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}
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int ff_flv_decode_picture_header(MpegEncContext *s)
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{
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    int format, width, height;
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    /* picture header */
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    if (get_bits_long(&s->gb, 17) != 1) {
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        av_log(s->avctx, AV_LOG_ERROR, "Bad picture start code\n");
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        return -1;
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    }
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    format = get_bits(&s->gb, 5);
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    if (format != 0 && format != 1) {
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        av_log(s->avctx, AV_LOG_ERROR, "Bad picture format\n");
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        return -1;
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    }
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    s->h263_flv = format+1;
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    s->picture_number = get_bits(&s->gb, 8); /* picture timestamp */
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    format = get_bits(&s->gb, 3);
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    switch (format) {
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    case 0:
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        width = get_bits(&s->gb, 8);
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        height = get_bits(&s->gb, 8);
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        break;
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    case 1:
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        width = get_bits(&s->gb, 16);
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        height = get_bits(&s->gb, 16);
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        break;
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    case 2:
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        width = 352;
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        height = 288;
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        break;
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    case 3:
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        width = 176;
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        height = 144;
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        break;
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    case 4:
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        width = 128;
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        height = 96;
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        break;
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    case 5:
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        width = 320;
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        height = 240;
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        break;
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    case 6:
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        width = 160;
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        height = 120;
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        break;
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    default:
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        width = height = 0;
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        break;
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    }
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    if(av_image_check_size(width, height, 0, s->avctx))
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        return -1;
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    s->width = width;
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    s->height = height;
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    s->pict_type = FF_I_TYPE + get_bits(&s->gb, 2);
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    s->dropable= s->pict_type > FF_P_TYPE;
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    if (s->dropable)
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        s->pict_type = FF_P_TYPE;
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    skip_bits1(&s->gb); /* deblocking flag */
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    s->chroma_qscale= s->qscale = get_bits(&s->gb, 5);
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    s->h263_plus = 0;
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    s->unrestricted_mv = 1;
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    s->h263_long_vectors = 0;
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    /* PEI */
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    while (get_bits1(&s->gb) != 0) {
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        skip_bits(&s->gb, 8);
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    }
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    s->f_code = 1;
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    if(s->avctx->debug & FF_DEBUG_PICT_INFO){
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        av_log(s->avctx, AV_LOG_DEBUG, "%c esc_type:%d, qp:%d num:%d\n",
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               s->dropable ? 'D' : av_get_pict_type_char(s->pict_type), s->h263_flv-1, s->qscale, s->picture_number);
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    }
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    s->y_dc_scale_table=
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    s->c_dc_scale_table= ff_mpeg1_dc_scale_table;
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    return 0;
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}
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AVCodec ff_flv_decoder = {
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    "flv",
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    AVMEDIA_TYPE_VIDEO,
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    CODEC_ID_FLV1,
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    sizeof(MpegEncContext),
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    ff_h263_decode_init,
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    NULL,
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    ff_h263_decode_end,
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    ff_h263_decode_frame,
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    CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1,
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    .max_lowres= 3,
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    .long_name= NULL_IF_CONFIG_SMALL("Flash Video (FLV) / Sorenson Spark / Sorenson H.263"),
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    .pix_fmts= ff_pixfmt_list_420,
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};