return 0;
}
-/* return the 8 bit start code value and update the search
- state. Return -1 if no start code found */
-static int find_start_code(const uint8_t **pbuf_ptr, const uint8_t *buf_end)
-{
- const uint8_t *buf_ptr= *pbuf_ptr;
-
- buf_ptr++; //gurantees that -1 is within the array
- buf_end -= 3; // gurantees that +3 is within the array
-
- while (buf_ptr < buf_end) {
- if(*buf_ptr==0){
- while(buf_ptr < buf_end && buf_ptr[1]==0)
- buf_ptr++;
-
- if(buf_ptr[-1] == 0 && buf_ptr[1] == 1){
- *pbuf_ptr = buf_ptr+3;
- return buf_ptr[2] + 0x100;
- }
- }
- buf_ptr += 2;
- }
- buf_end += 3; //undo the hack above
-
- *pbuf_ptr = buf_end;
- return -1;
-}
-
static int mpeg1_decode_picture(AVCodecContext *avctx,
const uint8_t *buf, int buf_size)
{
if(s->mb_y == s->end_mb_y)
return 0;
- start_code = find_start_code(&buf, s->gb.buffer_end);
+ start_code= -1;
+ buf = ff_find_start_code(buf, s->gb.buffer_end, &start_code);
mb_y= start_code - SLICE_MIN_START_CODE;
if(mb_y < 0 || mb_y >= s->end_mb_y)
return -1;
int ff_mpeg1_find_frame_end(ParseContext *pc, const uint8_t *buf, int buf_size)
{
int i;
- uint32_t state;
-
- state= pc->state;
+ uint32_t state= pc->state;
i=0;
if(!pc->frame_start_found){
for(i=0; i<buf_size; i++){
- state= (state<<8) | buf[i];
+ i= ff_find_start_code(buf+i, buf+buf_size, &state) - buf - 1;
if(state >= SLICE_MIN_START_CODE && state <= SLICE_MAX_START_CODE){
i++;
pc->frame_start_found=1;
if (buf_size == 0)
return 0;
for(; i<buf_size; i++){
- state= (state<<8) | buf[i];
+ i= ff_find_start_code(buf+i, buf+buf_size, &state) - buf - 1;
if((state&0xFFFFFF00) == 0x100){
if(state < SLICE_MIN_START_CODE || state > SLICE_MAX_START_CODE){
pc->frame_start_found=0;
for(;;) {
/* find start next code */
- start_code = find_start_code(&buf_ptr, buf_end);
+ start_code = -1;
+ buf_ptr = ff_find_start_code(buf_ptr,buf_end, &start_code);
if (start_code < 0){
if(s2->pict_type != B_TYPE || avctx->skip_frame <= AVDISCARD_DEFAULT){
if(avctx->thread_count > 1){
}
#endif //CONFIG_ENCODERS
+const uint8_t *ff_find_start_code(const uint8_t * restrict p, const uint8_t *end, uint32_t * restrict state){
+ int i;
+
+ for(i=0; i<3; i++){
+ uint32_t tmp= *state << 8;
+ *state= tmp + *(p++);
+ if(tmp == 0x100 || p==end)
+ return p;
+ }
+ p--; // need to recheck or might miss one
+ end--; // we need the byte after 00 00 01 too
+
+ while(p<end){
+ if (p[ 0] > 1) p+= 3;
+ else if(p[-1] ) p+= 2;
+ else if(p[-2]|(p[0]-1)) p++;
+ else{
+ p++;
+ break;
+ }
+ }
+
+ p= FFMIN(p, end)-3;
+ *state= be2me_32(unaligned32(p));
+
+ return p+4;
+}
+
/* init common dct for both encoder and decoder */
int DCT_common_init(MpegEncContext *s)
{
int ff_find_unused_picture(MpegEncContext *s, int shared);
void ff_denoise_dct(MpegEncContext *s, DCTELEM *block);
void ff_update_duplicate_context(MpegEncContext *dst, MpegEncContext *src);
+const uint8_t *ff_find_start_code(const uint8_t *p, const uint8_t *end, uint32_t *state);
void ff_er_frame_start(MpegEncContext *s);
void ff_er_frame_end(MpegEncContext *s);
return 0;
}
-static int find_start_code(const uint8_t **pbuf_ptr, const uint8_t *buf_end)
-{
- const uint8_t *buf_ptr;
- unsigned int state=0xFFFFFFFF, v;
- int val;
-
- buf_ptr = *pbuf_ptr;
- while (buf_ptr < buf_end) {
- v = *buf_ptr++;
- if (state == 0x000001) {
- state = ((state << 8) | v) & 0xffffff;
- val = state;
- goto found;
- }
- state = ((state << 8) | v) & 0xffffff;
- }
- val = -1;
- found:
- *pbuf_ptr = buf_ptr;
- return val;
-}
-
/* XXX: merge with libavcodec ? */
#define MPEG1_FRAME_RATE_BASE 1001
s->repeat_pict = 0;
buf_end = buf + buf_size;
while (buf < buf_end) {
- start_code = find_start_code(&buf, buf_end);
+ start_code= -1;
+ buf= ff_find_start_code(buf, buf_end, &start_code);
bytes_left = buf_end - buf;
switch(start_code) {
case PICTURE_START_CODE: