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libavformat
tmv.c
Go to the documentation of this file.
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/*
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* 8088flex TMV file demuxer
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* Copyright (c) 2009 Daniel Verkamp <daniel at drv.nu>
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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
8
* 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
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* 8088flex TMV file demuxer
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* @author Daniel Verkamp
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* @see http://www.oldskool.org/pc/8088_Corruption
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*/
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#include "
libavutil/channel_layout.h
"
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#include "
libavutil/intreadwrite.h
"
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#include "
avformat.h
"
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#include "
internal.h
"
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enum
{
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TMV_PADDING
= 0x01,
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TMV_STEREO
= 0x02,
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};
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#define TMV_TAG MKTAG('T', 'M', 'A', 'V')
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typedef
struct
TMVContext
{
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unsigned
audio_chunk_size
;
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unsigned
video_chunk_size
;
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unsigned
padding
;
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unsigned
stream_index
;
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}
TMVContext
;
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#define TMV_HEADER_SIZE 12
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#define PROBE_MIN_SAMPLE_RATE 5000
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#define PROBE_MAX_FPS 120
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#define PROBE_MIN_AUDIO_SIZE (PROBE_MIN_SAMPLE_RATE / PROBE_MAX_FPS)
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static
int
tmv_probe
(
AVProbeData
*p)
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{
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if
(
AV_RL32
(p->
buf
) ==
TMV_TAG
&&
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AV_RL16
(p->
buf
+4) >=
PROBE_MIN_SAMPLE_RATE
&&
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AV_RL16
(p->
buf
+6) >=
PROBE_MIN_AUDIO_SIZE
&&
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!p->
buf
[8] &&
// compression method
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p->
buf
[9] &&
// char cols
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p->
buf
[10])
// char rows
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return
AVPROBE_SCORE_MAX
/
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((p->
buf
[9] == 40 && p->
buf
[10] == 25) ? 1 : 4);
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return
0;
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}
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static
int
tmv_read_header
(
AVFormatContext
*
s
)
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{
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TMVContext
*tmv = s->
priv_data
;
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AVIOContext
*pb = s->
pb
;
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AVStream
*vst, *ast;
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AVRational
fps;
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unsigned
comp_method, char_cols, char_rows, features;
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if
(
avio_rl32
(pb) !=
TMV_TAG
)
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return
-1;
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if
(!(vst =
avformat_new_stream
(s, NULL)))
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return
AVERROR
(ENOMEM);
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if
(!(ast =
avformat_new_stream
(s, NULL)))
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return
AVERROR
(ENOMEM);
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ast->
codec
->
sample_rate
=
avio_rl16
(pb);
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if
(!ast->
codec
->
sample_rate
) {
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av_log
(s,
AV_LOG_ERROR
,
"invalid sample rate\n"
);
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return
-1;
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}
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tmv->
audio_chunk_size
=
avio_rl16
(pb);
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if
(!tmv->
audio_chunk_size
) {
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av_log
(s,
AV_LOG_ERROR
,
"invalid audio chunk size\n"
);
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return
-1;
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}
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comp_method =
avio_r8
(pb);
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if
(comp_method) {
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av_log
(s,
AV_LOG_ERROR
,
"unsupported compression method %d\n"
,
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comp_method);
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return
-1;
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}
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char_cols =
avio_r8
(pb);
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char_rows =
avio_r8
(pb);
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tmv->
video_chunk_size
= char_cols * char_rows * 2;
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features =
avio_r8
(pb);
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if
(features & ~(
TMV_PADDING
|
TMV_STEREO
)) {
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av_log
(s,
AV_LOG_ERROR
,
"unsupported features 0x%02x\n"
,
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features & ~(
TMV_PADDING
|
TMV_STEREO
));
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return
-1;
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}
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ast->
codec
->
codec_type
=
AVMEDIA_TYPE_AUDIO
;
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ast->
codec
->
codec_id
=
AV_CODEC_ID_PCM_U8
;
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if
(features &
TMV_STEREO
) {
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ast->
codec
->
channels
= 2;
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ast->
codec
->
channel_layout
=
AV_CH_LAYOUT_STEREO
;
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}
else
{
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ast->
codec
->
channels
= 1;
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ast->
codec
->
channel_layout
=
AV_CH_LAYOUT_MONO
;
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}
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ast->
codec
->
bits_per_coded_sample
= 8;
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ast->
codec
->
bit_rate
= ast->
codec
->
sample_rate
*
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ast->
codec
->
bits_per_coded_sample
;
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avpriv_set_pts_info
(ast, 32, 1, ast->
codec
->
sample_rate
);
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fps.
num
= ast->
codec
->
sample_rate
* ast->
codec
->
channels
;
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fps.
den
= tmv->
audio_chunk_size
;
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av_reduce
(&fps.
num
, &fps.
den
, fps.
num
, fps.
den
, 0xFFFFFFFFLL);
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vst->
codec
->
codec_type
=
AVMEDIA_TYPE_VIDEO
;
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vst->
codec
->
codec_id
=
AV_CODEC_ID_TMV
;
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vst->
codec
->
pix_fmt
=
AV_PIX_FMT_PAL8
;
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vst->
codec
->
width
= char_cols * 8;
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vst->
codec
->
height
= char_rows * 8;
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avpriv_set_pts_info
(vst, 32, fps.
den
, fps.
num
);
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if
(features &
TMV_PADDING
)
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tmv->
padding
=
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((tmv->
video_chunk_size
+ tmv->
audio_chunk_size
+ 511) & ~511) -
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(tmv->
video_chunk_size
+ tmv->
audio_chunk_size
);
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vst->
codec
->
bit_rate
= ((tmv->
video_chunk_size
+ tmv->
padding
) *
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fps.
num
* 8) / fps.
den
;
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return
0;
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}
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static
int
tmv_read_packet
(
AVFormatContext
*
s
,
AVPacket
*
pkt
)
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{
152
TMVContext
*tmv = s->
priv_data
;
153
AVIOContext
*pb = s->
pb
;
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int
ret
, pkt_size = tmv->
stream_index
?
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tmv->
audio_chunk_size
: tmv->
video_chunk_size
;
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if
(
url_feof
(pb))
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return
AVERROR_EOF
;
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ret =
av_get_packet
(pb, pkt, pkt_size);
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if
(tmv->
stream_index
)
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avio_skip
(pb, tmv->
padding
);
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pkt->
stream_index
= tmv->
stream_index
;
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tmv->
stream_index
^= 1;
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pkt->
flags
|=
AV_PKT_FLAG_KEY
;
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return
ret
;
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}
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static
int
tmv_read_seek
(
AVFormatContext
*
s
,
int
stream_index,
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int64_t timestamp,
int
flags
)
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{
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TMVContext
*tmv = s->
priv_data
;
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int64_t pos;
177
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if
(stream_index)
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return
-1;
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pos = timestamp *
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(tmv->
audio_chunk_size
+ tmv->
video_chunk_size
+ tmv->
padding
);
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if
(
avio_seek
(s->
pb
, pos +
TMV_HEADER_SIZE
, SEEK_SET) < 0)
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return
-1;
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tmv->
stream_index
= 0;
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return
0;
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}
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AVInputFormat
ff_tmv_demuxer
= {
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.
name
=
"tmv"
,
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.long_name =
NULL_IF_CONFIG_SMALL
(
"8088flex TMV"
),
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.priv_data_size =
sizeof
(
TMVContext
),
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.
read_probe
=
tmv_probe
,
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.
read_header
=
tmv_read_header
,
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.
read_packet
=
tmv_read_packet
,
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.
read_seek
=
tmv_read_seek
,
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.
flags
=
AVFMT_GENERIC_INDEX
,
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};
Generated on Sun Jul 20 2014 23:05:55 for FFmpeg by
1.8.2