0,0 → 1,167 |
/* |
* 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 *got_frame, |
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; |
GetBitContext hgb; /* for the header */ |
uint32_t dqt_offs, dht_offs, sof_offs, sos_offs, second_field_offs; |
uint32_t field_size, sod_offs; |
int ret; |
|
buf_ptr = buf; |
buf_end = buf + buf_size; |
s->got_picture = 0; |
|
read_header: |
/* reset on every SOI */ |
s->restart_interval = 0; |
s->restart_count = 0; |
s->mjpb_skiptosod = 0; |
|
if (buf_end - buf_ptr >= 1 << 28) |
return AVERROR_INVALIDDATA; |
|
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 AVERROR_INVALIDDATA; |
} |
|
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; |
if (ff_mjpeg_decode_dqt(s) < 0 && |
(avctx->err_recognition & AV_EF_EXPLODE)) |
return AVERROR_INVALIDDATA; |
} |
|
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_ptr + sos_offs, |
8 * FFMIN(field_size, buf_end - buf_ptr - sos_offs)); |
s->mjpb_skiptosod = (sod_offs - sos_offs - show_bits(&s->gb, 16)); |
s->start_code = SOS; |
if (ff_mjpeg_decode_sos(s, NULL, NULL) < 0 && |
(avctx->err_recognition & AV_EF_EXPLODE)) |
return AVERROR_INVALIDDATA; |
} |
|
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; |
goto read_header; |
} |
} |
|
//XXX FIXME factorize, this looks very similar to the EOI code |
|
if(!s->got_picture) { |
av_log(avctx, AV_LOG_WARNING, "no picture\n"); |
return buf_size; |
} |
|
if ((ret = av_frame_ref(data, s->picture_ptr)) < 0) |
return ret; |
*got_frame = 1; |
|
if (!s->lossless && avctx->debug & FF_DEBUG_QP) { |
av_log(avctx, AV_LOG_DEBUG, "QP: %d\n", |
FFMAX3(s->qscale[0], s->qscale[1], s->qscale[2])); |
} |
|
return buf_size; |
} |
|
AVCodec ff_mjpegb_decoder = { |
.name = "mjpegb", |
.long_name = NULL_IF_CONFIG_SMALL("Apple MJPEG-B"), |
.type = AVMEDIA_TYPE_VIDEO, |
.id = AV_CODEC_ID_MJPEGB, |
.priv_data_size = sizeof(MJpegDecodeContext), |
.init = ff_mjpeg_decode_init, |
.close = ff_mjpeg_decode_end, |
.decode = mjpegb_decode_frame, |
.capabilities = CODEC_CAP_DR1, |
.max_lowres = 3, |
}; |