mirror of
https://git.videolan.org/git/ffmpeg.git
synced 2024-08-18 07:15:04 +02:00
162 lines
5.2 KiB
C
162 lines
5.2 KiB
C
/*
|
|
* Apple MJPEG-B decoder
|
|
* Copyright (c) 2002 Alex Beregszaszi
|
|
*
|
|
* This file is part of FFmpeg.
|
|
*
|
|
* FFmpeg is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU Lesser General Public
|
|
* License as published by the Free Software Foundation; either
|
|
* version 2.1 of the License, or (at your option) any later version.
|
|
*
|
|
* FFmpeg is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
* Lesser General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU Lesser General Public
|
|
* License along with FFmpeg; if not, write to the Free Software
|
|
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
|
|
*/
|
|
|
|
/**
|
|
* @file
|
|
* Apple MJPEG-B decoder.
|
|
*/
|
|
|
|
#include "avcodec.h"
|
|
#include "mjpeg.h"
|
|
#include "mjpegdec.h"
|
|
|
|
static uint32_t read_offs(AVCodecContext *avctx, GetBitContext *gb, uint32_t size, const char *err_msg){
|
|
uint32_t offs= get_bits_long(gb, 32);
|
|
if(offs >= size){
|
|
av_log(avctx, AV_LOG_WARNING, err_msg, offs, size);
|
|
return 0;
|
|
}
|
|
return offs;
|
|
}
|
|
|
|
static int mjpegb_decode_frame(AVCodecContext *avctx,
|
|
void *data, int *data_size,
|
|
AVPacket *avpkt)
|
|
{
|
|
const uint8_t *buf = avpkt->data;
|
|
int buf_size = avpkt->size;
|
|
MJpegDecodeContext *s = avctx->priv_data;
|
|
const uint8_t *buf_end, *buf_ptr;
|
|
AVFrame *picture = data;
|
|
GetBitContext hgb; /* for the header */
|
|
uint32_t dqt_offs, dht_offs, sof_offs, sos_offs, second_field_offs;
|
|
uint32_t field_size, sod_offs;
|
|
|
|
buf_ptr = buf;
|
|
buf_end = buf + buf_size;
|
|
|
|
read_header:
|
|
/* reset on every SOI */
|
|
s->restart_interval = 0;
|
|
s->restart_count = 0;
|
|
s->mjpb_skiptosod = 0;
|
|
|
|
init_get_bits(&hgb, buf_ptr, /*buf_size*/(buf_end - buf_ptr)*8);
|
|
|
|
skip_bits(&hgb, 32); /* reserved zeros */
|
|
|
|
if (get_bits_long(&hgb, 32) != MKBETAG('m','j','p','g'))
|
|
{
|
|
av_log(avctx, AV_LOG_WARNING, "not mjpeg-b (bad fourcc)\n");
|
|
return 0;
|
|
}
|
|
|
|
field_size = get_bits_long(&hgb, 32); /* field size */
|
|
av_log(avctx, AV_LOG_DEBUG, "field size: 0x%x\n", field_size);
|
|
skip_bits(&hgb, 32); /* padded field size */
|
|
second_field_offs = read_offs(avctx, &hgb, buf_end - buf_ptr, "second_field_offs is %d and size is %d\n");
|
|
av_log(avctx, AV_LOG_DEBUG, "second field offs: 0x%x\n", second_field_offs);
|
|
|
|
dqt_offs = read_offs(avctx, &hgb, buf_end - buf_ptr, "dqt is %d and size is %d\n");
|
|
av_log(avctx, AV_LOG_DEBUG, "dqt offs: 0x%x\n", dqt_offs);
|
|
if (dqt_offs)
|
|
{
|
|
init_get_bits(&s->gb, buf_ptr+dqt_offs, (buf_end - (buf_ptr+dqt_offs))*8);
|
|
s->start_code = DQT;
|
|
ff_mjpeg_decode_dqt(s);
|
|
}
|
|
|
|
dht_offs = read_offs(avctx, &hgb, buf_end - buf_ptr, "dht is %d and size is %d\n");
|
|
av_log(avctx, AV_LOG_DEBUG, "dht offs: 0x%x\n", dht_offs);
|
|
if (dht_offs)
|
|
{
|
|
init_get_bits(&s->gb, buf_ptr+dht_offs, (buf_end - (buf_ptr+dht_offs))*8);
|
|
s->start_code = DHT;
|
|
ff_mjpeg_decode_dht(s);
|
|
}
|
|
|
|
sof_offs = read_offs(avctx, &hgb, buf_end - buf_ptr, "sof is %d and size is %d\n");
|
|
av_log(avctx, AV_LOG_DEBUG, "sof offs: 0x%x\n", sof_offs);
|
|
if (sof_offs)
|
|
{
|
|
init_get_bits(&s->gb, buf_ptr+sof_offs, (buf_end - (buf_ptr+sof_offs))*8);
|
|
s->start_code = SOF0;
|
|
if (ff_mjpeg_decode_sof(s) < 0)
|
|
return -1;
|
|
}
|
|
|
|
sos_offs = read_offs(avctx, &hgb, buf_end - buf_ptr, "sos is %d and size is %d\n");
|
|
av_log(avctx, AV_LOG_DEBUG, "sos offs: 0x%x\n", sos_offs);
|
|
sod_offs = read_offs(avctx, &hgb, buf_end - buf_ptr, "sof is %d and size is %d\n");
|
|
av_log(avctx, AV_LOG_DEBUG, "sod offs: 0x%x\n", sod_offs);
|
|
if (sos_offs)
|
|
{
|
|
// init_get_bits(&s->gb, buf+sos_offs, (buf_end - (buf+sos_offs))*8);
|
|
init_get_bits(&s->gb, buf_ptr+sos_offs, field_size*8);
|
|
s->mjpb_skiptosod = (sod_offs - sos_offs - show_bits(&s->gb, 16));
|
|
s->start_code = SOS;
|
|
ff_mjpeg_decode_sos(s);
|
|
}
|
|
|
|
if (s->interlaced) {
|
|
s->bottom_field ^= 1;
|
|
/* if not bottom field, do not output image yet */
|
|
if (s->bottom_field != s->interlace_polarity && second_field_offs)
|
|
{
|
|
buf_ptr = buf + second_field_offs;
|
|
second_field_offs = 0;
|
|
goto read_header;
|
|
}
|
|
}
|
|
|
|
//XXX FIXME factorize, this looks very similar to the EOI code
|
|
|
|
*picture= s->picture;
|
|
*data_size = sizeof(AVFrame);
|
|
|
|
if(!s->lossless){
|
|
picture->quality= FFMAX3(s->qscale[0], s->qscale[1], s->qscale[2]);
|
|
picture->qstride= 0;
|
|
picture->qscale_table= s->qscale_table;
|
|
memset(picture->qscale_table, picture->quality, (s->width+15)/16);
|
|
if(avctx->debug & FF_DEBUG_QP)
|
|
av_log(avctx, AV_LOG_DEBUG, "QP: %d\n", picture->quality);
|
|
picture->quality*= FF_QP2LAMBDA;
|
|
}
|
|
|
|
return buf_ptr - buf;
|
|
}
|
|
|
|
AVCodec mjpegb_decoder = {
|
|
"mjpegb",
|
|
AVMEDIA_TYPE_VIDEO,
|
|
CODEC_ID_MJPEGB,
|
|
sizeof(MJpegDecodeContext),
|
|
ff_mjpeg_decode_init,
|
|
NULL,
|
|
ff_mjpeg_decode_end,
|
|
mjpegb_decode_frame,
|
|
CODEC_CAP_DR1,
|
|
NULL,
|
|
.max_lowres = 3,
|
|
.long_name = NULL_IF_CONFIG_SMALL("Apple MJPEG-B"),
|
|
};
|