mirror of
https://github.com/FFmpeg/FFmpeg.git
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130 lines
3.8 KiB
C
130 lines
3.8 KiB
C
/*
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* FLV decoding.
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg 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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* FFmpeg 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 FFmpeg; 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 "libavutil/imgutils.h"
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#include "flv.h"
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#include "h263dec.h"
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#include "mpegvideo.h"
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#include "mpegvideodata.h"
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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(&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 AVERROR_INVALIDDATA;
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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 AVERROR_INVALIDDATA;
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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 AVERROR(EINVAL);
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s->width = width;
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s->height = height;
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s->pict_type = AV_PICTURE_TYPE_I + get_bits(&s->gb, 2);
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s->droppable = s->pict_type > AV_PICTURE_TYPE_P;
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if (s->droppable)
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s->pict_type = AV_PICTURE_TYPE_P;
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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->h263_long_vectors = 0;
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/* PEI */
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if (skip_1stop_8data_bits(&s->gb) < 0)
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return AVERROR_INVALIDDATA;
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s->f_code = 1;
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if (s->ehc_mode)
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s->avctx->sample_aspect_ratio= (AVRational){1,2};
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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->droppable ? 'D' : av_get_picture_type_char(s->pict_type),
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s->h263_flv - 1, s->qscale, s->picture_number);
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}
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s->y_dc_scale_table = s->c_dc_scale_table = ff_mpeg1_dc_scale_table;
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return 0;
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}
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const AVCodec ff_flv_decoder = {
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.name = "flv",
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.long_name = NULL_IF_CONFIG_SMALL("FLV / Sorenson Spark / Sorenson H.263 (Flash Video)"),
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.type = AVMEDIA_TYPE_VIDEO,
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.id = AV_CODEC_ID_FLV1,
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.priv_data_size = sizeof(MpegEncContext),
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.init = ff_h263_decode_init,
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.close = ff_h263_decode_end,
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.decode = ff_h263_decode_frame,
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.capabilities = AV_CODEC_CAP_DRAW_HORIZ_BAND | AV_CODEC_CAP_DR1,
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.caps_internal = FF_CODEC_CAP_SKIP_FRAME_FILL_PARAM,
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.max_lowres = 3,
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.pix_fmts = (const enum AVPixelFormat[]) { AV_PIX_FMT_YUV420P,
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AV_PIX_FMT_NONE },
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};
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