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libavcodec
msrle.c
Go to the documentation of this file.
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/*
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* Microsoft RLE video decoder
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* Copyright (C) 2003 the ffmpeg project
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*
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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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31
#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "
avcodec.h
"
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#include "
internal.h
"
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#include "
msrledec.h
"
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typedef
struct
MsrleContext
{
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AVCodecContext
*
avctx
;
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AVFrame
*
frame
;
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GetByteContext
gb
;
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const
unsigned
char
*
buf
;
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int
size
;
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uint32_t
pal
[256];
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}
MsrleContext
;
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static
av_cold
int
msrle_decode_init
(
AVCodecContext
*avctx)
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{
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MsrleContext
*s = avctx->
priv_data
;
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s->
avctx
= avctx;
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switch
(avctx->
bits_per_coded_sample
) {
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case
4:
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case
8:
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avctx->
pix_fmt
=
AV_PIX_FMT_PAL8
;
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break
;
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case
24:
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avctx->
pix_fmt
=
AV_PIX_FMT_BGR24
;
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break
;
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default
:
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av_log
(avctx,
AV_LOG_ERROR
,
"unsupported bits per sample\n"
);
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return
AVERROR_INVALIDDATA
;
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}
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s->
frame
=
av_frame_alloc
();
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if
(!s->
frame
)
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return
AVERROR
(ENOMEM);
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return
0;
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}
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static
int
msrle_decode_frame
(
AVCodecContext
*avctx,
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void
*
data
,
int
*got_frame,
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AVPacket
*avpkt)
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{
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const
uint8_t
*buf = avpkt->
data
;
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int
buf_size = avpkt->
size
;
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MsrleContext
*s = avctx->
priv_data
;
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int
istride =
FFALIGN
(avctx->
width
*avctx->
bits_per_coded_sample
, 32) / 8;
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int
ret;
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s->
buf
= buf;
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s->
size
= buf_size;
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if
((ret =
ff_reget_buffer
(avctx, s->
frame
)) < 0) {
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av_log
(avctx,
AV_LOG_ERROR
,
"reget_buffer() failed\n"
);
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return
ret;
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}
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if
(avctx->
bits_per_coded_sample
<= 8) {
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const
uint8_t
*pal =
av_packet_get_side_data
(avpkt,
AV_PKT_DATA_PALETTE
,
NULL
);
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if
(pal) {
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s->
frame
->
palette_has_changed
= 1;
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memcpy(s->
pal
, pal,
AVPALETTE_SIZE
);
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}
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/* make the palette available */
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memcpy(s->
frame
->
data
[1], s->
pal
,
AVPALETTE_SIZE
);
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}
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/* FIXME how to correctly detect RLE ??? */
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if
(avctx->
height
* istride == avpkt->
size
) {
/* assume uncompressed */
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int
linesize = avctx->
width
* avctx->
bits_per_coded_sample
/ 8;
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uint8_t
*ptr = s->
frame
->
data
[0];
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uint8_t
*buf = avpkt->
data
+ (avctx->
height
-1)*istride;
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int
i, j;
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for
(i = 0; i < avctx->
height
; i++) {
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if
(avctx->
bits_per_coded_sample
== 4) {
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for
(j = 0; j < avctx->
width
- 1; j += 2) {
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ptr[j+0] = buf[j>>1] >> 4;
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ptr[j+1] = buf[j>>1] & 0xF;
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}
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if
(avctx->
width
& 1)
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ptr[j+0] = buf[j>>1] >> 4;
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}
else
{
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memcpy(ptr, buf, linesize);
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}
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buf -= istride;
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ptr += s->
frame
->
linesize
[0];
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}
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}
else
{
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bytestream2_init
(&s->
gb
, buf, buf_size);
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ff_msrle_decode
(avctx, (
AVPicture
*)s->
frame
, avctx->
bits_per_coded_sample
, &s->
gb
);
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}
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if
((ret =
av_frame_ref
(data, s->
frame
)) < 0)
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return
ret;
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*got_frame = 1;
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/* report that the buffer was completely consumed */
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return
buf_size;
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}
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static
av_cold
int
msrle_decode_end
(
AVCodecContext
*avctx)
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{
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MsrleContext
*s = avctx->
priv_data
;
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/* release the last frame */
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av_frame_free
(&s->
frame
);
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return
0;
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}
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AVCodec
ff_msrle_decoder
= {
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.
name
=
"msrle"
,
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.long_name =
NULL_IF_CONFIG_SMALL
(
"Microsoft RLE"
),
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.type =
AVMEDIA_TYPE_VIDEO
,
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.id =
AV_CODEC_ID_MSRLE
,
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.priv_data_size =
sizeof
(
MsrleContext
),
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.
init
=
msrle_decode_init
,
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.
close
=
msrle_decode_end
,
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.
decode
=
msrle_decode_frame
,
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.capabilities =
CODEC_CAP_DR1
,
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};
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