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avformat/dv: implement fallback in dv_extract_pack() 

Fixes Ticket2340
Fixes Ticket2341

Based-on mail from Dave Rice <dave@dericed.com>
Tested-by: Dave Rice <dave@dericed.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
Michael Niedermayer 2014-07-17 04:25:21 +02:00
parent e5cb7795fc
commit 88f038ac97
1 changed files with 23 additions and 20 deletions
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43
libavformat/dv.c
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@ -72,30 +72,33 @@ static inline uint16_t dv_audio_12to16(uint16_t sample)
return result;
}
/*
* This is the dumbest implementation of all -- it simply looks at
* a fixed offset and if pack isn't there -- fails. We might want
* to have a fallback mechanism for complete search of missing packs.
*/
static const uint8_t *dv_extract_pack(uint8_t *frame, enum dv_pack_type t)
{
int offs;
int c;
switch (t) {
case dv_audio_source:
offs = (80 * 6 + 80 * 16 * 3 + 3);
break;
case dv_audio_control:
offs = (80 * 6 + 80 * 16 * 4 + 3);
break;
case dv_video_control:
offs = (80 * 5 + 48 + 5);
break;
case dv_timecode:
offs = (80*1 + 3 + 3);
break;
default:
return NULL;
for (c = 0; c < 10; c++) {
switch (t) {
case dv_audio_source:
if (c&1) offs = (80 * 6 + 80 * 16 * 0 + 3 + c*12000);
else offs = (80 * 6 + 80 * 16 * 3 + 3 + c*12000);
break;
case dv_audio_control:
if (c&1) offs = (80 * 6 + 80 * 16 * 1 + 3 + c*12000);
else offs = (80 * 6 + 80 * 16 * 4 + 3 + c*12000);
break;
case dv_video_control:
if (c&1) offs = (80 * 3 + 8 + c*12000);
else offs = (80 * 5 + 48 + 5 + c*12000);
break;
case dv_timecode:
offs = (80*1 + 3 + 3);
break;
default:
return NULL;
}
if (frame[offs] == t)
break;
}
return frame[offs] == t ? &frame[offs] : NULL;