Hello, I've been trying to solve some timestamp issues with v4l2 in GStreamer and tracked down the problem to be the uvc driver giving back non-monotonic (sometimes decreasing) timestamp. Here's some traces I have captured. It shows the TS as computed by uvc_video_clock_update(). Notice that before this call the TS are monotonic. This method is far from trivial, so any help would be appreciated. [21967.375107] uvcvideo: Built-in iSight: SOF 3140.137924 y 1435759049 ts 21967.778560 buf ts 21967.338765 (x1 177340416/146/661 x2 179437568/178/692 y1 1000000000 y2 1032119492) [21967.426928] uvcvideo: Built-in iSight: SOF 3140.136291 y 1382052758 ts 21967.776903 buf ts 21967.390830 (x1 180748288/198/712 x2 182845440/230/743 y1 1000000000 y2 1031993005) [21967.475141] uvcvideo: Built-in iSight: SOF 3140.137893 y 1332485681 ts 21967.779230 buf ts 21967.438749 (x1 184156160/250/762 x2 185991168/278/793 y1 1000000000 y2 1028199123) [21967.526930] uvcvideo: Built-in iSight: SOF 3140.137878 y 1282023868 ts 21967.776877 buf ts 21967.490838 (x1 187301888/298/812 x2 189399040/330/843 y1 1000000000 y2 1031987069) [21967.566957] uvcvideo: Built-in iSight: SOF 3140.136322 y 1238515894 ts 21967.777348 buf ts 21967.530792 (x1 190185472/342/854 x2 192020480/370/885 y1 1000000000 y2 1028044630) [21967.610926] uvcvideo: Built-in iSight: SOF 3140.136337 y 1198142764 ts 21967.776997 buf ts 21967.574767 (x1 192806912/382/896 x2 194904064/414/927 y1 1000000000 y2 1032001038) [21967.650930] uvcvideo: Built-in iSight: SOF 3140.137817 y 1158528823 ts 21967.777309 buf ts 21967.614754 (x1 195428352/422/937 x2 197525504/454/968 y1 1000000000 y2 1032079122) [21967.694920] uvcvideo: Built-in iSight: SOF 3140.139266 y 1114141225 ts 21967.776985 buf ts 21967.658756 (x1 198311936/466/979 x2 200409088/498/1010 y1 1000000000 y2 1032000549) [21967.734945] uvcvideo: Built-in iSight: SOF 3140.139221 y 1074227386 ts 21967.777055 buf ts 21967.698774 (x1 200933376/506/1021 x2 203030528/538/1052 y1 1000000000 y2 1032038054) [21967.778916] uvcvideo: Built-in iSight: SOF 3140.137802 y 1030136608 ts 21967.776983 buf ts 21967.738775 (x1 203816960/550/1063 x2 205914112/582/1094 y1 1000000000 y2 1031998733) [21967.818956] uvcvideo: Built-in iSight: SOF 3140.136413 y 990110109 ts 21967.776897 buf ts 21967.782775 (x1 206438400/590/1105 x2 208535552/622/1136 y1 1000000000 y2 1032085338) [21967.862985] uvcvideo: Built-in iSight: SOF 3140.137756 y 946020732 ts 21967.776868 buf ts 21967.822761 (x1 209321984/634/1146 x2 211156992/662/1177 y1 1000000000 y2 1028060834) [21967.902940] uvcvideo: Built-in iSight: SOF 3140.137741 y 906078361 ts 21967.776911 buf ts 21967.866805 (x1 211943424/674/1188 x2 214040576/706/1219 y1 1000000000 y2 1032020244) [21967.942962] uvcvideo: Built-in iSight: SOF 3140.137725 y 861471274 ts 21967.776231 buf ts 21967.906780 (x1 214827008/718/1230 x2 216662016/746/1261 y1 1000000000 y2 1028135357) [21967.986951] uvcvideo: Built-in iSight: SOF 3140.138961 y 821880474 ts 21967.776661 buf ts 21967.950779 (x1 217448448/758/1272 x2 219545600/790/1303 y1 1000000000 y2 1032046506) [21968.026956] uvcvideo: Built-in iSight: SOF 3140.138931 y 777744906 ts 21967.776585 buf ts 21967.990787 (x1 220332032/802/1314 x2 222167040/830/1345 y1 1000000000 y2 1028049728) [21968.070933] uvcvideo: Built-in iSight: SOF 3140.137695 y 738230942 ts 21967.777101 buf ts 21968.034766 (x1 222953472/842/1356 x2 225050624/874/1387 y1 1000000000 y2 1031988605) [21968.110982] uvcvideo: Built-in iSight: SOF 3140.136535 y 698058220 ts 21967.776936 buf ts 21968.074822 (x1 225574912/882/1397 x2 227672064/914/1428 y1 1000000000 y2 1032008302) [21968.154936] uvcvideo: Built-in iSight: SOF 3140.136535 y 654680157 ts 21967.777540 buf ts 21968.118769 (x1 228458496/926/1439 x2 230555648/958/1470 y1 1000000000 y2 1031949703) [21968.194962] uvcvideo: Built-in iSight: SOF 3140.136550 y 613663361 ts 21967.776502 buf ts 21968.158787 (x1 231079936/966/1481 x2 233177088/998/1512 y1 1000000000 y2 1032039242) cheers, Nicolas -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
