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libavformat
bfi.c
Go to the documentation of this file.
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/*
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* Brute Force & Ignorance (BFI) demuxer
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* Copyright (c) 2008 Sisir Koppaka
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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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29
#include "
libavutil/intreadwrite.h
"
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#include "
avformat.h
"
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#include "
internal.h
"
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typedef
struct
BFIContext
{
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int
nframes
;
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int
audio_frame
;
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int
video_frame
;
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int
video_size
;
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int
avflag
;
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}
BFIContext
;
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static
int
bfi_probe
(
AVProbeData
* p)
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{
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/* Check file header */
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if
(
AV_RL32
(p->
buf
) ==
MKTAG
(
'B'
,
'F'
,
'&'
,
'I'
))
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return
AVPROBE_SCORE_MAX
;
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else
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return
0;
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}
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static
int
bfi_read_header
(
AVFormatContext
* s,
AVFormatParameters
* ap)
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{
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BFIContext
*bfi = s->
priv_data
;
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AVIOContext
*pb = s->
pb
;
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AVStream
*vstream;
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AVStream
*astream;
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int
fps, chunk_header;
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/* Initialize the video codec... */
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vstream =
avformat_new_stream
(s,
NULL
);
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if
(!vstream)
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return
AVERROR
(ENOMEM);
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/* Initialize the audio codec... */
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astream =
avformat_new_stream
(s,
NULL
);
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if
(!astream)
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return
AVERROR
(ENOMEM);
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/* Set the total number of frames. */
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avio_skip
(pb, 8);
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chunk_header =
avio_rl32
(pb);
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bfi->
nframes
=
avio_rl32
(pb);
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avio_rl32
(pb);
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avio_rl32
(pb);
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avio_rl32
(pb);
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fps =
avio_rl32
(pb);
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avio_skip
(pb, 12);
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vstream->
codec
->
width
=
avio_rl32
(pb);
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vstream->
codec
->
height
=
avio_rl32
(pb);
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/*Load the palette to extradata */
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avio_skip
(pb, 8);
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vstream->
codec
->
extradata
=
av_malloc
(768);
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vstream->
codec
->
extradata_size
= 768;
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avio_read
(pb, vstream->
codec
->
extradata
,
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vstream->
codec
->
extradata_size
);
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astream->
codec
->
sample_rate
=
avio_rl32
(pb);
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/* Set up the video codec... */
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avpriv_set_pts_info
(vstream, 32, 1, fps);
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vstream->
codec
->
codec_type
=
AVMEDIA_TYPE_VIDEO
;
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vstream->
codec
->
codec_id
=
CODEC_ID_BFI
;
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vstream->
codec
->
pix_fmt
=
PIX_FMT_PAL8
;
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/* Set up the audio codec now... */
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astream->
codec
->
codec_type
=
AVMEDIA_TYPE_AUDIO
;
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astream->
codec
->
codec_id
=
CODEC_ID_PCM_U8
;
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astream->
codec
->
channels
= 1;
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astream->
codec
->
bits_per_coded_sample
= 8;
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astream->
codec
->
bit_rate
=
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astream->
codec
->
sample_rate
* astream->
codec
->
bits_per_coded_sample
;
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avio_seek
(pb, chunk_header - 3, SEEK_SET);
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avpriv_set_pts_info
(astream, 64, 1, astream->
codec
->
sample_rate
);
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return
0;
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}
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static
int
bfi_read_packet
(
AVFormatContext
* s,
AVPacket
* pkt)
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{
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BFIContext
*bfi = s->
priv_data
;
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AVIOContext
*pb = s->
pb
;
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int
ret, audio_offset, video_offset, chunk_size,
audio_size
= 0;
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if
(bfi->
nframes
== 0 || pb->
eof_reached
) {
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return
AVERROR
(EIO);
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}
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/* If all previous chunks were completely read, then find a new one... */
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if
(!bfi->
avflag
) {
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uint32_t
state
= 0;
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while
(state !=
MKTAG
(
'S'
,
'A'
,
'V'
,
'I'
)){
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if
(pb->
eof_reached
)
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return
AVERROR
(EIO);
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state = 256*state +
avio_r8
(pb);
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}
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/* Now that the chunk's location is confirmed, we proceed... */
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chunk_size =
avio_rl32
(pb);
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avio_rl32
(pb);
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audio_offset =
avio_rl32
(pb);
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avio_rl32
(pb);
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video_offset =
avio_rl32
(pb);
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audio_size = video_offset - audio_offset;
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bfi->
video_size
= chunk_size - video_offset;
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if
(audio_size < 0 || bfi->
video_size
< 0) {
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av_log
(s,
AV_LOG_ERROR
,
"Invalid audio/video offsets or chunk size\n"
);
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return
AVERROR_INVALIDDATA
;
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}
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//Tossing an audio packet at the audio decoder.
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ret =
av_get_packet
(pb, pkt, audio_size);
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if
(ret < 0)
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return
ret;
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pkt->
pts
= bfi->
audio_frame
;
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bfi->
audio_frame
+= ret;
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}
else
if
(bfi->
video_size
> 0) {
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//Tossing a video packet at the video decoder.
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ret =
av_get_packet
(pb, pkt, bfi->
video_size
);
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if
(ret < 0)
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return
ret;
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pkt->
pts
= bfi->
video_frame
;
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bfi->
video_frame
+= ret / bfi->
video_size
;
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/* One less frame to read. A cursory decrement. */
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bfi->
nframes
--;
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}
else
{
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/* Empty video packet */
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ret =
AVERROR
(EAGAIN);
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}
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bfi->
avflag
= !bfi->
avflag
;
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pkt->
stream_index
= bfi->
avflag
;
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return
ret;
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}
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AVInputFormat
ff_bfi_demuxer
= {
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.
name
=
"bfi"
,
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.long_name =
NULL_IF_CONFIG_SMALL
(
"Brute Force & Ignorance"
),
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.priv_data_size =
sizeof
(
BFIContext
),
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.
read_probe
=
bfi_probe
,
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.
read_header
=
bfi_read_header
,
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.
read_packet
=
bfi_read_packet
,
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};