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Another hack to allow the Cinepak decoder to detect both types of deviant Cinepak 

data. Tested against both known FILM files, several CPK files, and normal
CVID-encoded files.

Originally committed as revision 7215 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Mike Melanson 2006-12-02 22:27:18 +00:00
parent b40a061fcb
commit 10f865c9b7
1 changed files with 28 additions and 8 deletions
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36
libavcodec/cinepak.c
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@ -26,6 +26,8 @@
* by Ewald Snel <ewald@rambo.its.tudelft.nl>
* For more information on the Cinepak algorithm, visit:
* http://www.csse.monash.edu.au/~timf/
* For more information on the quirky data inside Sega FILM/CPK files, visit:
* http://wiki.multimedia.cx/index.php?title=Sega_FILM
*/
#include <stdio.h>
@ -67,6 +69,8 @@ typedef struct CinepakContext {
int palette_video;
cvid_strip_t strips[MAX_STRIPS];
int sega_film_skip_bytes;
} CinepakContext;
static void cinepak_decode_codebook (cvid_codebook_t *codebook,
@ -319,8 +323,6 @@ static int cinepak_decode (CinepakContext *s)
int i, result, strip_size, frame_flags, num_strips;
int y0 = 0;
int encoded_buf_size;
/* if true, Cinepak data is from a Sega FILM/CPK file */
int sega_film_data = 0;
if (s->size < 10)
return -1;
@ -328,12 +330,29 @@ static int cinepak_decode (CinepakContext *s)
frame_flags = s->data[0];
num_strips = BE_16 (&s->data[8]);
encoded_buf_size = ((s->data[1] << 16) | BE_16 (&s->data[2]));
if (encoded_buf_size != s->size)
sega_film_data = 1;
if (sega_film_data)
s->data += 12;
else
s->data += 10;
/* if this is the first frame, check for deviant Sega FILM data */
if (s->sega_film_skip_bytes == -1) {
if (encoded_buf_size != s->size) {
/* If the encoded frame size differs from the frame size as indicated
* by the container file, this data likely comes from a Sega FILM/CPK file.
* If the frame header is followed by the bytes FE 00 00 06 00 00 then
* this is probably one of the two known files that have 6 extra bytes
* after the frame header. Else, assume 2 extra bytes. */
if ((s->data[10] == 0xFE) &&
(s->data[11] == 0x00) &&
(s->data[12] == 0x00) &&
(s->data[13] == 0x06) &&
(s->data[14] == 0x00) &&
(s->data[15] == 0x00))
s->sega_film_skip_bytes = 6;
else
s->sega_film_skip_bytes = 2;
} else
s->sega_film_skip_bytes = 0;
}
s->data += 10 + s->sega_film_skip_bytes;
if (num_strips > MAX_STRIPS)
num_strips = MAX_STRIPS;
@ -377,6 +396,7 @@ static int cinepak_decode_init(AVCodecContext *avctx)
s->avctx = avctx;
s->width = (avctx->width + 3) & ~3;
s->height = (avctx->height + 3) & ~3;
s->sega_film_skip_bytes = -1; /* uninitialized state */
// check for paletted data
if ((avctx->palctrl == NULL) || (avctx->bits_per_sample == 40)) {