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lpms: calculate similarity per audio packet (#352)

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This commit is contained in:
Oscar
2022-07-28 16:45:27 +08:00
committed by GitHub
parent 35888364c2
commit dacf4ac6ff
1 changed files with 59 additions and 11 deletions
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ffmpeg/extras.c
+59 -11
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@@ -6,13 +6,20 @@
#include "extras.h"
#include "logging.h"
#define MAX_AMISMATCH 10
#define INC_MD5_COUNT 300
#define MAX_MD5_COUNT 30000
#define MD5_SIZE 16 //sizeof(int)*4 byte
struct match_info {
int width;
int height;
uint64_t bit_rate;
int packetcount; //video total packet count
uint64_t timestamp; //XOR sum of avpacket pts
int audiosum[4]; //XOR sum of audio data's md5(16 bytes)
int packetcount; //video total packet count
uint64_t timestamp; //XOR sum of avpacket pts
int md5allocsize;
int apacketcount; //audio packet count
int *pmd5array;
};
struct buffer_data {
@@ -341,9 +348,23 @@ static int get_matchinfo(void *buffer, int len, struct match_info* info)
}
info->packetcount++;
info->timestamp ^= packet->pts;
if(packet->stream_index == audioid && packet->pts > 0 && packet->size > 0) {
av_md5_sum((uint8_t*)md5tmp, packet->data, packet->size);
for (int i=0; i<4; i++) info->audiosum[i] ^= md5tmp[i];
if (packet->stream_index == audioid && packet->size > 0) {
if (info->apacketcount < MAX_MD5_COUNT) {
info->apacketcount++;
if (info->apacketcount > info->md5allocsize) {
info->md5allocsize += INC_MD5_COUNT;
if (info->pmd5array == NULL) {
info->pmd5array = (int*)av_malloc(info->md5allocsize*MD5_SIZE);
} else {
int* tmp = info->pmd5array;
info->pmd5array = (int*)av_malloc(info->md5allocsize*MD5_SIZE);
memcpy(info->pmd5array, tmp, (info->md5allocsize-INC_MD5_COUNT)*MD5_SIZE);
av_free(tmp);
}
}
int* pint = info->pmd5array + (info->apacketcount-1) * 4;
av_md5_sum((uint8_t*)(pint), packet->data, packet->size);
}
}
av_packet_unref(packet);
}
@@ -358,7 +379,31 @@ clean:
avformat_close_input(&ifmt_ctx);
return ret;
}
// check validity for audio md5 data
bool is_valid_md5data(struct match_info* info1, struct match_info *info2)
{
#define max(a, b) ((a) > (b) ? (a) : (b))
#define min(a, b) ((a) < (b) ? (a) : (b))
struct match_info* first = info1->apacketcount < info2->apacketcount? info1: info2;
struct match_info* second = info1->apacketcount >= info2->apacketcount? info1: info2;
int packetdiff = second->apacketcount - first->apacketcount;
if (packetdiff > MAX_AMISMATCH) return false;
int matchingcount = 0;
for (int i = 0; i < first->apacketcount; i++) {
int scanscope = packetdiff + 1;
int *psrcmpd = first->pmd5array + (i*4);
int nstart = max(0,i-scanscope);
int nend = min(second->apacketcount,i+scanscope);
for (int j = nstart; j < nend; j++) {
if(memcmp(psrcmpd, second->pmd5array + (j*4), MD5_SIZE) == 0){
matchingcount++;
break;
}
}
}
int realdiff = first->apacketcount - matchingcount;
return realdiff < MAX_AMISMATCH ? true: false;
}
// compare two video buffers whether those matches or not.
// @param buffer1 the pointer of the first video buffer.
// @param buffer2 the pointer of the second video buffer.
@@ -368,17 +413,20 @@ clean:
int lpms_compare_video_bybuffer(void *buffer1, int len1, void *buffer2, int len2)
{
int ret = 0;
struct match_info info1, info2;
struct match_info info1 = {0,}, info2 = {0,};
ret = get_matchinfo(buffer1,len1,&info1);
if(ret < 0) return ret;
if(ret < 0) goto clean;
ret = get_matchinfo(buffer2,len2,&info2);
if(ret < 0) return ret;
if(ret < 0) goto clean;
//compare two matching information
if (info1.width != info2.width || info1.height != info2.height || memcmp(info1.audiosum, info2.audiosum, 16)) {
if (info1.width != info2.width || info1.height != info2.height || !is_valid_md5data(&info1, &info2)) {
ret = 1;
}
clean:
if(info1.pmd5array) av_free(info1.pmd5array);
if(info2.pmd5array) av_free(info2.pmd5array);
return ret;
}