feat(ffmpeg): select frame by duration and float position

ffmpeg/ffmpeg.go

@@ -243,9 +243,7 @@ func incrementDuration(av *AVContext, frame *C.AVFrame, i C.int) {
 		ptsToNano := C.int64_t(1000000000 * av.stream.time_base.num / av.stream.time_base.den)
 		newDuration := time.Duration(frame.pts * ptsToNano)
 		av.availableDuration = newDuration
-		if av.selectedDuration > 0 && i > 0 && newDuration <= av.selectedDuration {
+
-			av.selectedIndex = i
-		}
 		if !av.durationInFormat && newDuration > av.duration {
 			av.duration = newDuration
 		}
@@ -325,6 +323,13 @@ func populateThumbContext(av *AVContext, frames chan *C.AVFrame, n C.int, done <
 		incrementDuration(av, frame, i)
 		frames <- frame
 		frame = nil
+		if av.selectedDuration > 0 {
+			if av.availableDuration <= av.selectedDuration {
+				av.selectedIndex = i
+			} else {
+				break
+			}
+		}
 	}
 	if av.selectedIndex > av.availableIndex {
 		av.selectedIndex = av.availableIndex

ffmpeg/ffmpeg_test.go

@@ -72,7 +72,7 @@ func TestAVContext(t *testing.T) {
 				if n == 10 {
 					require.NoError(t, av.ProcessFrames(n))
 				} else if n == 99999 {
-					require.NoError(t, av.SelectDuration(time.Millisecond*500))
+					require.NoError(t, av.SelectDuration(time.Second))
 				} else if n == 9999 {
 					require.NoError(t, av.SelectPosition(0.7))
 				} else if n > -1 {

testdata/golden/meta/alpha-webm.webm-9999.meta.json

@@ -1 +1 @@
-{"orientation":1,"duration":12040,"width":720,"height":576,"fps":10.9,"has_video":true,"has_audio":false}
+{"orientation":1,"duration":12040,"width":720,"height":576,"fps":9.8,"has_video":true,"has_audio":false}

testdata/golden/meta/everybody-betray-me.mkv-9999.meta.json

@@ -1 +1 @@
-{"orientation":1,"duration":7407,"width":640,"height":480,"fps":9.3,"has_video":true,"has_audio":true}
+{"orientation":1,"duration":7407,"width":640,"height":480,"fps":1.2,"has_video":true,"has_audio":true}

testdata/golden/meta/everybody-betray-me.mkv-99999.meta.json

@@ -1 +1 @@
-{"orientation":1,"duration":7407,"width":640,"height":480,"fps":26.3,"has_video":true,"has_audio":true}
+{"orientation":1,"duration":7407,"width":640,"height":480,"fps":16,"has_video":true,"has_audio":true}

testdata/golden/meta/schizo.flv-9999.meta.json

@@ -1 +1 @@
-{"orientation":1,"duration":2560,"width":480,"height":360,"fps":29.7,"has_video":true,"has_audio":true}
+{"orientation":1,"duration":2560,"width":480,"height":360,"fps":29.6,"has_video":true,"has_audio":true}

testdata/golden/meta/schizo.flv-99999.meta.json

@@ -1 +1 @@
-{"orientation":1,"duration":2560,"width":480,"height":360,"fps":29.7,"has_video":true,"has_audio":true}
+{"orientation":1,"duration":2560,"width":480,"height":360,"fps":29.3,"has_video":true,"has_audio":true}