mirror of https://github.com/FFmpeg/FFmpeg.git
Originally committed as revision 9073 to svn://svn.ffmpeg.org/ffmpeg/trunkpull/126/head
Aurelien Jacobs
18 years ago
parent
82ec791834
commit
0a59a18b4e
4 changed files with 166 additions and 134 deletions
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/*
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* Apple MJPEG-B decoder |
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* Copyright (c) 2002 Alex Beregszaszi |
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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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/**
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* @file mjpegbdec.c |
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* Apple MJPEG-B decoder. |
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*/ |
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#include "avcodec.h" |
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#include "mjpeg.h" |
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#include "mjpegdec.h" |
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static int mjpegb_decode_frame(AVCodecContext *avctx, |
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void *data, int *data_size, |
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uint8_t *buf, int buf_size) |
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{ |
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MJpegDecodeContext *s = avctx->priv_data; |
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uint8_t *buf_end, *buf_ptr; |
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AVFrame *picture = data; |
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GetBitContext hgb; /* for the header */ |
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uint32_t dqt_offs, dht_offs, sof_offs, sos_offs, second_field_offs; |
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uint32_t field_size, sod_offs; |
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buf_ptr = buf; |
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buf_end = buf + buf_size; |
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read_header: |
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/* reset on every SOI */ |
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s->restart_interval = 0; |
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s->restart_count = 0; |
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s->mjpb_skiptosod = 0; |
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init_get_bits(&hgb, buf_ptr, /*buf_size*/(buf_end - buf_ptr)*8); |
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skip_bits(&hgb, 32); /* reserved zeros */ |
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if (get_bits_long(&hgb, 32) != MKBETAG('m','j','p','g')) |
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{ |
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av_log(avctx, AV_LOG_WARNING, "not mjpeg-b (bad fourcc)\n"); |
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return 0; |
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} |
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field_size = get_bits_long(&hgb, 32); /* field size */ |
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av_log(avctx, AV_LOG_DEBUG, "field size: 0x%x\n", field_size); |
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skip_bits(&hgb, 32); /* padded field size */ |
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second_field_offs = get_bits_long(&hgb, 32); |
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av_log(avctx, AV_LOG_DEBUG, "second field offs: 0x%x\n", second_field_offs); |
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dqt_offs = get_bits_long(&hgb, 32); |
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av_log(avctx, AV_LOG_DEBUG, "dqt offs: 0x%x\n", dqt_offs); |
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if (dqt_offs) |
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{ |
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init_get_bits(&s->gb, buf+dqt_offs, (buf_end - (buf+dqt_offs))*8); |
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s->start_code = DQT; |
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ff_mjpeg_decode_dqt(s); |
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} |
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dht_offs = get_bits_long(&hgb, 32); |
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av_log(avctx, AV_LOG_DEBUG, "dht offs: 0x%x\n", dht_offs); |
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if (dht_offs) |
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{ |
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init_get_bits(&s->gb, buf+dht_offs, (buf_end - (buf+dht_offs))*8); |
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s->start_code = DHT; |
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ff_mjpeg_decode_dht(s); |
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} |
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sof_offs = get_bits_long(&hgb, 32); |
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av_log(avctx, AV_LOG_DEBUG, "sof offs: 0x%x\n", sof_offs); |
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if (sof_offs) |
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{ |
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init_get_bits(&s->gb, buf+sof_offs, (buf_end - (buf+sof_offs))*8); |
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s->start_code = SOF0; |
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if (ff_mjpeg_decode_sof(s) < 0) |
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return -1; |
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} |
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sos_offs = get_bits_long(&hgb, 32); |
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av_log(avctx, AV_LOG_DEBUG, "sos offs: 0x%x\n", sos_offs); |
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sod_offs = get_bits_long(&hgb, 32); |
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av_log(avctx, AV_LOG_DEBUG, "sod offs: 0x%x\n", sod_offs); |
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if (sos_offs) |
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{ |
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// init_get_bits(&s->gb, buf+sos_offs, (buf_end - (buf+sos_offs))*8);
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init_get_bits(&s->gb, buf+sos_offs, field_size*8); |
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s->mjpb_skiptosod = (sod_offs - sos_offs - show_bits(&s->gb, 16)); |
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s->start_code = SOS; |
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ff_mjpeg_decode_sos(s); |
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} |
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if (s->interlaced) { |
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s->bottom_field ^= 1; |
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/* if not bottom field, do not output image yet */ |
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if (s->bottom_field && second_field_offs) |
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{ |
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buf_ptr = buf + second_field_offs; |
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second_field_offs = 0; |
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goto read_header; |
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} |
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} |
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//XXX FIXME factorize, this looks very similar to the EOI code
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*picture= s->picture; |
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*data_size = sizeof(AVFrame); |
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if(!s->lossless){ |
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picture->quality= FFMAX(FFMAX(s->qscale[0], s->qscale[1]), s->qscale[2]); |
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picture->qstride= 0; |
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picture->qscale_table= s->qscale_table; |
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memset(picture->qscale_table, picture->quality, (s->width+15)/16); |
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if(avctx->debug & FF_DEBUG_QP) |
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av_log(avctx, AV_LOG_DEBUG, "QP: %d\n", picture->quality); |
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picture->quality*= FF_QP2LAMBDA; |
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} |
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return buf_ptr - buf; |
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} |
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AVCodec mjpegb_decoder = { |
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"mjpegb", |
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CODEC_TYPE_VIDEO, |
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CODEC_ID_MJPEGB, |
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sizeof(MJpegDecodeContext), |
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ff_mjpeg_decode_init, |
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NULL, |
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ff_mjpeg_decode_end, |
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mjpegb_decode_frame, |
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CODEC_CAP_DR1, |
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NULL |
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}; |
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