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https://git.videolan.org/git/ffmpeg.git
synced 2024-08-27 11:51:49 +02:00
faster find_startcode()
Originally committed as revision 4939 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
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8f0df75438
commit
82fcbc145d
@ -2171,33 +2171,6 @@ static int mpeg_decode_postinit(AVCodecContext *avctx){
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return 0;
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}
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/* return the 8 bit start code value and update the search
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state. Return -1 if no start code found */
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static int find_start_code(const uint8_t **pbuf_ptr, const uint8_t *buf_end)
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{
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const uint8_t *buf_ptr= *pbuf_ptr;
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buf_ptr++; //gurantees that -1 is within the array
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buf_end -= 3; // gurantees that +3 is within the array
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while (buf_ptr < buf_end) {
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if(*buf_ptr==0){
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while(buf_ptr < buf_end && buf_ptr[1]==0)
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buf_ptr++;
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if(buf_ptr[-1] == 0 && buf_ptr[1] == 1){
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*pbuf_ptr = buf_ptr+3;
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return buf_ptr[2] + 0x100;
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}
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}
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buf_ptr += 2;
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}
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buf_end += 3; //undo the hack above
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*pbuf_ptr = buf_end;
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return -1;
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}
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static int mpeg1_decode_picture(AVCodecContext *avctx,
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const uint8_t *buf, int buf_size)
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{
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@ -2715,7 +2688,8 @@ static int slice_decode_thread(AVCodecContext *c, void *arg){
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if(s->mb_y == s->end_mb_y)
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return 0;
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start_code = find_start_code(&buf, s->gb.buffer_end);
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start_code= -1;
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buf = ff_find_start_code(buf, s->gb.buffer_end, &start_code);
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mb_y= start_code - SLICE_MIN_START_CODE;
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if(mb_y < 0 || mb_y >= s->end_mb_y)
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return -1;
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@ -2995,14 +2969,12 @@ static void mpeg_decode_gop(AVCodecContext *avctx,
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int ff_mpeg1_find_frame_end(ParseContext *pc, const uint8_t *buf, int buf_size)
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{
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int i;
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uint32_t state;
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state= pc->state;
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uint32_t state= pc->state;
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i=0;
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if(!pc->frame_start_found){
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for(i=0; i<buf_size; i++){
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state= (state<<8) | buf[i];
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i= ff_find_start_code(buf+i, buf+buf_size, &state) - buf - 1;
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if(state >= SLICE_MIN_START_CODE && state <= SLICE_MAX_START_CODE){
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i++;
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pc->frame_start_found=1;
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@ -3016,7 +2988,7 @@ int ff_mpeg1_find_frame_end(ParseContext *pc, const uint8_t *buf, int buf_size)
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if (buf_size == 0)
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return 0;
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for(; i<buf_size; i++){
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state= (state<<8) | buf[i];
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i= ff_find_start_code(buf+i, buf+buf_size, &state) - buf - 1;
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if((state&0xFFFFFF00) == 0x100){
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if(state < SLICE_MIN_START_CODE || state > SLICE_MAX_START_CODE){
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pc->frame_start_found=0;
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@ -3083,7 +3055,8 @@ static int mpeg_decode_frame(AVCodecContext *avctx,
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for(;;) {
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/* find start next code */
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start_code = find_start_code(&buf_ptr, buf_end);
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start_code = -1;
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buf_ptr = ff_find_start_code(buf_ptr,buf_end, &start_code);
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if (start_code < 0){
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if(s2->pict_type != B_TYPE || avctx->skip_frame <= AVDISCARD_DEFAULT){
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if(avctx->thread_count > 1){
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@ -228,6 +228,34 @@ void ff_write_quant_matrix(PutBitContext *pb, int16_t *matrix){
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}
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#endif //CONFIG_ENCODERS
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const uint8_t *ff_find_start_code(const uint8_t * restrict p, const uint8_t *end, uint32_t * restrict state){
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int i;
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for(i=0; i<3; i++){
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uint32_t tmp= *state << 8;
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*state= tmp + *(p++);
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if(tmp == 0x100 || p==end)
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return p;
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}
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p--; // need to recheck or might miss one
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end--; // we need the byte after 00 00 01 too
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while(p<end){
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if (p[ 0] > 1) p+= 3;
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else if(p[-1] ) p+= 2;
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else if(p[-2]|(p[0]-1)) p++;
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else{
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p++;
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break;
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}
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}
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p= FFMIN(p, end)-3;
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*state= be2me_32(unaligned32(p));
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return p+4;
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}
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/* init common dct for both encoder and decoder */
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int DCT_common_init(MpegEncContext *s)
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{
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@ -773,6 +773,7 @@ void ff_write_quant_matrix(PutBitContext *pb, int16_t *matrix);
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int ff_find_unused_picture(MpegEncContext *s, int shared);
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void ff_denoise_dct(MpegEncContext *s, DCTELEM *block);
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void ff_update_duplicate_context(MpegEncContext *dst, MpegEncContext *src);
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const uint8_t *ff_find_start_code(const uint8_t *p, const uint8_t *end, uint32_t *state);
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void ff_er_frame_start(MpegEncContext *s);
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void ff_er_frame_end(MpegEncContext *s);
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@ -272,28 +272,6 @@ int ff_combine_frame(ParseContext *pc, int next, uint8_t **buf, int *buf_size)
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return 0;
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}
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static int find_start_code(const uint8_t **pbuf_ptr, const uint8_t *buf_end)
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{
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const uint8_t *buf_ptr;
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unsigned int state=0xFFFFFFFF, v;
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int val;
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buf_ptr = *pbuf_ptr;
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while (buf_ptr < buf_end) {
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v = *buf_ptr++;
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if (state == 0x000001) {
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state = ((state << 8) | v) & 0xffffff;
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val = state;
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goto found;
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}
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state = ((state << 8) | v) & 0xffffff;
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}
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val = -1;
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found:
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*pbuf_ptr = buf_ptr;
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return val;
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}
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/* XXX: merge with libavcodec ? */
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#define MPEG1_FRAME_RATE_BASE 1001
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@ -335,7 +313,8 @@ static void mpegvideo_extract_headers(AVCodecParserContext *s,
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s->repeat_pict = 0;
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buf_end = buf + buf_size;
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while (buf < buf_end) {
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start_code = find_start_code(&buf, buf_end);
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start_code= -1;
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buf= ff_find_start_code(buf, buf_end, &start_code);
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bytes_left = buf_end - buf;
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switch(start_code) {
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case PICTURE_START_CODE:
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