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Improve accuracy of frame rate calculation. #6

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Improve accuracy of frame rate calculation. #6

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15 changes: 12 additions & 3 deletions yamdi.c
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Original file line number Diff line number Diff line change
Expand Up @@ -149,6 +149,7 @@ typedef struct {

// Calculated values
size_t ntags; // # of video tags
size_t nframetags; // # of actual frame tags (not sequence headers)
double framerate; // ntags / duration
double datarate; // datasize / duration
uint64_t datasize; // Size of the video data
Expand Down Expand Up @@ -709,6 +710,7 @@ int freeFLV(FLV_t *flv) {
int analyzeFLV(FLV_t *flv, FILE *fp) {
int rv;
size_t i, index;
unsigned char flagBytes[2];
unsigned char flags;
FLVTag_t *flvtag;

Expand Down Expand Up @@ -767,7 +769,13 @@ int analyzeFLV(FLV_t *flv, FILE *fp) {
flv->video.lasttimestamp = flvtag->timestamp;
flv->video.lastframeindex = i;

readFLVTagData(&flags, 1, flvtag, fp);
readFLVTagData(flagBytes, 2, flvtag, fp);
flags = flagBytes[0];

// All non-H.264 video tags, and all H.264 NALU tags, should be actual video frames.
if (((flags & 0xf) != 7) || (flagBytes[1] == 1)) {
flv->video.nframetags++;
}

// Keyframes
flvtag->keyframe = (flags >> 4) & 0xf;
Expand Down Expand Up @@ -862,8 +870,8 @@ int analyzeFLV(FLV_t *flv, FILE *fp) {
#endif

// Calculate video framerate
if(flv->video.ntags != 0)
flv->video.framerate = (double)flv->video.ntags / (double)flv->video.lasttimestamp * 1000.0;
if(flv->video.nframetags > 1)
flv->video.framerate = ((double)flv->video.nframetags - 1) / (double)flv->video.lasttimestamp * 1000.0;

// Calculate video datarate
if(flv->video.datasize != 0)
Expand All @@ -874,6 +882,7 @@ int analyzeFLV(FLV_t *flv, FILE *fp) {
fprintf(stderr, "[FLV] video.lasttimestamp = %d ms\n", flv->video.lasttimestamp);
fprintf(stderr, "[FLV] video.lastframeindex = %d\n", flv->video.lastframeindex);
fprintf(stderr, "[FLV] video.ntags = %d\n", flv->video.ntags);
fprintf(stderr, "[FLV] video.nframetags = %d\n", flv->video.nframetags);
fprintf(stderr, "[FLV] video.framerate = %f fps\n", flv->video.framerate);
fprintf(stderr, "[FLV] video.datasize = %" PRIu64 " kb\n", flv->video.datasize);
fprintf(stderr, "[FLV] video.datarate = %f kbit/s\n", flv->video.datarate);
Expand Down