Code refactoring for FFmpeg producer

Author: AlexxIT

internal/ffmpeg/ffmpeg.go

@@ -92,8 +92,6 @@ var defaults = map[string]string{
 	"pcml/8000":  "-c:a pcm_s16le -ar:a 8000 -ac:a 1",
 	"pcml/44100": "-c:a pcm_s16le -ar:a 44100 -ac:a 1",
 
-	"opus/48000/2": "-c:a libopus -application:a lowdelay -min_comp 0 -ar:a 48000 -ac:a 2",
-
 	// hardware Intel and AMD on Linux
 	// better not to set `-async_depth:v 1` like for QSV, because framedrops
 	// `-bf 0` - disable B-frames is very important

internal/ffmpeg/producer.go

@@ -34,16 +34,19 @@ func NewProducer(url string) (core.Producer, error) {
 	p.Type = "FFmpeg producer"
 	p.Medias = []*core.Media{
 		{
+			// we can support only audio, because don't know FmtpLine for H264 and PayloadType for MJPEG
 			Kind:      core.KindAudio,
 			Direction: core.DirectionRecvonly,
+			// codecs in order from best to worst
 			Codecs: []*core.Codec{
+				// OPUS will always marked as OPUS/48000/2
 				{Name: core.CodecOpus, ClockRate: 48000, Channels: 2},
 				{Name: core.CodecAAC, ClockRate: 16000, FmtpLine: aac.FMTP + "1408"},
 				{Name: core.CodecPCM, ClockRate: 16000},
-				{Name: core.CodecPCM, ClockRate: 8000},
 				{Name: core.CodecPCMA, ClockRate: 16000},
-				{Name: core.CodecPCMA, ClockRate: 8000},
 				{Name: core.CodecPCMU, ClockRate: 16000},
+				{Name: core.CodecPCM, ClockRate: 8000},
+				{Name: core.CodecPCMA, ClockRate: 8000},
 				{Name: core.CodecPCMU, ClockRate: 8000},
 			},
 		},
@@ -96,7 +99,7 @@ func (p *Producer) newURL() string {
 		case core.CodecAAC:
 			s += "#audio=aac/16000"
 		case core.CodecOpus:
-			s += "#audio=opus/48000/2"
+			s += "#audio=opus"
 		}
 	}
 	// add other params