* 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>
int palette_video;
cvid_strip_t strips[MAX_STRIPS];
+ int sega_film_skip_bytes;
+
} CinepakContext;
static void cinepak_decode_codebook (cvid_codebook_t *codebook,
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;
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;
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)) {