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libavformat
tta.c
Go to the documentation of this file.
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/*
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* TTA demuxer
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* Copyright (c) 2006 Alex Beregszaszi
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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
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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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* 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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#include "
libavcodec/get_bits.h
"
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#include "
avformat.h
"
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#include "
internal.h
"
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#include "
id3v1.h
"
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#include "
libavutil/dict.h
"
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typedef
struct
{
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int
totalframes
, currentframe;
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int
frame_size
;
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int
last_frame_size
;
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}
TTAContext
;
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static
int
tta_probe
(
AVProbeData
*p)
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{
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const
uint8_t
*d = p->
buf
;
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if
(d[0] ==
'T'
&& d[1] ==
'T'
&& d[2] ==
'A'
&& d[3] ==
'1'
)
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return
80;
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return
0;
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}
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static
int
tta_read_header
(
AVFormatContext
*s)
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{
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TTAContext
*
c
= s->
priv_data
;
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AVStream
*st;
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int
i, channels,
bps
, samplerate;
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uint64_t framepos, start_offset;
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uint32_t datalen;
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if
(!
av_dict_get
(s->
metadata
,
""
,
NULL
,
AV_DICT_IGNORE_SUFFIX
))
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ff_id3v1_read
(s);
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start_offset =
avio_tell
(s->
pb
);
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if
(
avio_rl32
(s->
pb
) !=
AV_RL32
(
"TTA1"
))
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return
-1;
// not tta file
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avio_skip
(s->
pb
, 2);
// FIXME: flags
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channels =
avio_rl16
(s->
pb
);
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bps =
avio_rl16
(s->
pb
);
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samplerate =
avio_rl32
(s->
pb
);
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if
(samplerate <= 0 || samplerate > 1000000){
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av_log
(s,
AV_LOG_ERROR
,
"nonsense samplerate\n"
);
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return
-1;
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}
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datalen =
avio_rl32
(s->
pb
);
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if
(!datalen) {
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av_log
(s,
AV_LOG_ERROR
,
"invalid datalen\n"
);
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return
AVERROR_INVALIDDATA
;
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}
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avio_skip
(s->
pb
, 4);
// header crc
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c->
frame_size
= samplerate * 256 / 245;
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c->
last_frame_size
= datalen % c->
frame_size
;
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if
(!c->
last_frame_size
)
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c->
last_frame_size
= c->
frame_size
;
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c->
totalframes
= datalen / c->
frame_size
+ (c->
last_frame_size
< c->
frame_size
);
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c->
currentframe
= 0;
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if
(c->
totalframes
>= UINT_MAX/
sizeof
(uint32_t) || c->
totalframes
<= 0){
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av_log
(s,
AV_LOG_ERROR
,
"totalframes %d invalid\n"
, c->
totalframes
);
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return
-1;
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}
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st =
avformat_new_stream
(s,
NULL
);
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if
(!st)
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return
AVERROR
(ENOMEM);
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avpriv_set_pts_info
(st, 64, 1, samplerate);
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st->
start_time
= 0;
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st->
duration
= datalen;
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framepos =
avio_tell
(s->
pb
) + 4*c->
totalframes
+ 4;
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for
(i = 0; i < c->
totalframes
; i++) {
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uint32_t
size
=
avio_rl32
(s->
pb
);
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av_add_index_entry
(st, framepos, i * c->
frame_size
, size, 0,
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AVINDEX_KEYFRAME
);
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framepos +=
size
;
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}
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avio_skip
(s->
pb
, 4);
// seektable crc
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st->
codec
->
codec_type
=
AVMEDIA_TYPE_AUDIO
;
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st->
codec
->
codec_id
=
AV_CODEC_ID_TTA
;
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st->
codec
->
channels
= channels;
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st->
codec
->
sample_rate
= samplerate;
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st->
codec
->
bits_per_coded_sample
=
bps
;
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st->
codec
->
extradata_size
=
avio_tell
(s->
pb
) - start_offset;
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if
(st->
codec
->
extradata_size
+
FF_INPUT_BUFFER_PADDING_SIZE
<= (
unsigned
)st->
codec
->
extradata_size
){
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//this check is redundant as avio_read should fail
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av_log
(s,
AV_LOG_ERROR
,
"extradata_size too large\n"
);
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return
-1;
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}
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st->
codec
->
extradata
=
av_mallocz
(st->
codec
->
extradata_size
+
FF_INPUT_BUFFER_PADDING_SIZE
);
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if
(!st->
codec
->
extradata
) {
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st->
codec
->
extradata_size
= 0;
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return
AVERROR
(ENOMEM);
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}
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avio_seek
(s->
pb
, start_offset, SEEK_SET);
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avio_read
(s->
pb
, st->
codec
->
extradata
, st->
codec
->
extradata_size
);
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return
0;
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}
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static
int
tta_read_packet
(
AVFormatContext
*s,
AVPacket
*
pkt
)
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{
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TTAContext
*
c
= s->
priv_data
;
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AVStream
*st = s->
streams
[0];
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int
size
, ret;
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// FIXME!
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if
(c->
currentframe
>= c->
totalframes
)
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return
AVERROR_EOF
;
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size = st->
index_entries
[c->
currentframe
].
size
;
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ret =
av_get_packet
(s->
pb
, pkt, size);
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pkt->
dts
= st->
index_entries
[c->
currentframe
++].
timestamp
;
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pkt->
duration
= c->
currentframe
== c->
totalframes
? c->
last_frame_size
:
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c->
frame_size
;
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return
ret;
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}
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static
int
tta_read_seek
(
AVFormatContext
*s,
int
stream_index, int64_t timestamp,
int
flags
)
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{
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TTAContext
*
c
= s->
priv_data
;
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AVStream
*st = s->
streams
[stream_index];
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int
index
=
av_index_search_timestamp
(st, timestamp, flags);
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if
(index < 0)
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return
-1;
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if
(
avio_seek
(s->
pb
, st->
index_entries
[index].
pos
, SEEK_SET) < 0)
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return
-1;
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c->
currentframe
=
index
;
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return
0;
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}
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AVInputFormat
ff_tta_demuxer
= {
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.
name
=
"tta"
,
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.long_name =
NULL_IF_CONFIG_SMALL
(
"TTA (True Audio)"
),
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.priv_data_size =
sizeof
(
TTAContext
),
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.
read_probe
=
tta_probe
,
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.
read_header
=
tta_read_header
,
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.
read_packet
=
tta_read_packet
,
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.
read_seek
=
tta_read_seek
,
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.extensions =
"tta"
,
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};
Generated on Sat May 25 2013 04:01:11 for FFmpeg by
1.8.2