使用Gstreamer接收音频流导致未协商错误的原因

Question

I would like to stream audio data from MIC with Gstreamer. However I could not play MIC audio with rx. How can I play audio stream from MIC input?

tx: gst-launch-1.0 -v alsasrc device="hw:0" ! decodebin ! audioconvert ! rtpL16pay ! queue ! udpsink host=239.0.0.1 auto-multicast=true port=5004

rx: gst-launch-1.0 udpsrc multicast-group=239.0.0.1 port=5004 caps="application/x-rtp" ! rtpL16depay ! alsasink

rx result: Setting pipeline to PAUSED ... Pipeline is live and does not need PREROLL ... Setting pipeline to PLAYING ... New clock: GstSystemClock ERROR: from element /GstPipeline:pipeline0/GstUDPSrc:udpsrc0: Internal data flow error. Additional debug info: ../../../../gstreamer-1.8.1/libs/gst/base/gstbasesrc.c(2948): gst_base_src_loop (): /GstPipeline:pipeline0/GstUDPSrc:udpsrc0: streaming task paused, reason not-negotiated (-4) Execution ended after 0:00:00.009364000 Setting pipeline to PAUSED ... Setting pipeline to READY ... Setting pipeline to NULL ... Freeing pipeline ...

tx result is as follows.

Setting pipeline to PAUSED ... Pipeline is live and does not need PREROLL ... Setting pipeline to PLAYING ... New clock: GstAudioSrcClock /GstPipeline:pipeline0/GstAlsaSrc:alsasrc0: actual-buffer-time = 200000 /GstPipeline:pipeline0/GstAlsaSrc:alsasrc0: actual-latency-time = 10000 /GstPipeline:pipeline0/GstAlsaSrc:alsasrc0.GstPad:src: caps = "audio/x-raw\\,\\ format\\=(string)S16LE\\,\\ layout\\=(string)interleaved\\,\\ rate\\=(int)44100\\,\\ channels\\=(int)2\\,\\ channel-mask\\=(bitmask)0x0000000000000003" /GstPipeline:pipeline0/GstDecodeBin:decodebin0.GstGhostPad:sink.GstProxyPad:proxypad0: caps = "audio/x-raw\\,\\ format\\=(string)S16LE\\,\\ layout\\=(string)interleaved\\,\\ rate\\=(int)44100\\,\\ channels\\=(int)2\\,\\ channel-mask\\=(bitmask)0x0000000000000003" /GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstTypeFindElement:typefind.GstPad:src: caps = "audio/x-raw\\,\\ format\\=(string)S16LE\\,\\ layout\\=(string)interleaved\\,\\ rate\\=(int)44100\\,\\ channels\\=(int)2\\,\\ channel-mask\\=(bitmask)0x0000000000000003" Red istribute latency... /GstPipeline:pipeline0/GstAudioConvert:audioconvert0.GstPad:src: caps = "audio/x-raw\\,\\ layout\\=(string)interleaved\\,\\ rate\\=(int)44100\\,\\ format\\=(string)S16BE\\,\\ channels\\=(int)2\\,\\ channel-mask\\=(bitmask)0x0000000000000003" /GstPipeline:pipeline0/GstRtpL16Pay:rtpl16pay0.GstPad:src: caps = "application/x-rtp\\,\\ media\\=(string)audio\\,\\ clock-rate\\=(int)44100\\,\\ encoding-name\\=(string)L16\\,\\ encoding-params\\=(string)2\\,\\ channels\\=(int)2\\,\\ payload\\=(int)96\\,\\ ssrc\\=(uint)3961155089\\,\\ timestamp-offset\\=(uint)725507323\\,\\ seqnum-offset\\=(uint)20783" /GstPipeline:pipeline0/GstQueue:queue0.GstPad:src: caps = "application/x-rtp\\,\\ media\\=(string)audio\\,\\ clock-rate\\=(int)44100\\,\\ encoding-name\\=(string)L16\\,\\ encoding-params\\=(string)2\\,\\ channels\\=(int)2\\,\\ payload\\=(int)96\\,\\ ssrc\\=(uint)3961155089\\,\\ timestamp-offset\\=(uint)725507323\\,\\ seqnum-offset\\=(uint)20783" /GstPipeline:pipeline0/GstUDPSink:udpsink0.GstPad:sink: caps = "application/x-rtp\\,\\ media\\=(string)au dio\\,\\ clock-rate\\=(int)44100\\,\\ encoding-name\\=(string)L16\\,\\ encoding-params\\=(string)2\\,\\ channels\\=(int)2\\,\\ payload\\=(int)96\\,\\ ssrc\\=(uint)3961155089\\,\\ timestamp-offset\\=(uint)725507323\\,\\ seqnum-offset\\=(uint)20783" /GstPipeline:pipeline0/GstQueue:queue0.GstPad:sink: caps = "application/x-rtp\\,\\ media\\=(string)audio\\,\\ clock-rate\\=(int)44100\\,\\ encoding-name\\=(string)L16\\,\\ encoding-params\\=(string)2\\,\\ channels\\=(int)2\\,\\ payload\\=(int)96\\,\\ ssrc\\=(uint)3961155089\\,\\ timestamp-offset\\=(uint)725507323\\,\\ seqnum-offset\\=(uint)20783" /GstPipeline:pipeline0/GstRtpL16Pay:rtpl16pay0.GstPad:sink: caps = "audio/x-raw\\,\\ layout\\=(string)interleaved\\,\\ rate\\=(int)44100\\,\\ format\\=(string)S16BE\\,\\ channels\\=(int)2\\,\\ channel-mask\\=(bitmask)0x0000000000000003" /GstPipeline:pipeline0/GstAudioConvert:audioconvert0.GstPad:sink: caps = "audio/x-raw\\,\\ format\\=(string)S16LE\\,\\ layout\\=(string)interleaved\\,\\ rate\\=(int)44100\\,\\ channels\\=(int)2\\,\\ channel-mask\\=(bitmask)0x0000000000000003" /Gst Pipeline:pipeline0/GstDecodeBin:decodebin0.GstDecodePad:src_0.GstProxyPad:proxypad1: caps = "audio/x-raw\\,\\ format\\=(string)S16LE\\,\\ layout\\=(string)interleaved\\,\\ rate\\=(int)44100\\,\\ channels\\=(int)2\\,\\ channel-mask\\=(bitmask)0x0000000000000003" /GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstTypeFindElement:typefind.GstPad:sink: caps = "audio/x-raw\\,\\ format\\=(string)S16LE\\,\\ layout\\=(string)interleaved\\,\\ rate\\=(int)44100\\,\\ channels\\=(int)2\\,\\ channel-mask\\=(bitmask)0x0000000000000003" /GstPipeline:pipeline0/GstDecodeBin:decodebin0.GstGhostPad:sink: caps = "audio/x-raw\\,\\ format\\=(string)S16LE\\,\\ layout\\=(string)interleaved\\,\\ rate\\=(int)44100\\,\\ channels\\=(int)2\\,\\ channel-mask\\=(bitmask)0x0000000000000003" /GstPipeline:pipeline0/GstRtpL16Pay:rtpl16pay0: timestamp = 725507323 /GstPipeline:pipeline0/GstRtpL16Pay:rtpl16pay0: seqnum = 20783

I think rx pipeline is wrong, but I could not find the solution. Please tell me how to make pipeline.

PS: I tried following command, and rx play the mic audio! This means the reciever device is not able to play L16 audio?

tx: gst-launch-1.0 -v alsasrc device="hw:0" ! decodebin ! audioconvert ! audioresample ! alawenc ! rtppcmapay ! queue ! udpsink host=239.0.0.1 auto-multicast=true port=5004

rx: gst-launch-1.0 udpsrc multicast-group=239.0.0.1 port=5004 caps="application/x-rtp, media=(string)audio, clock-rate=(int)8000, encoding-name=(string)PCMA, encoding-params=(string)2, channels=(int)1, payload=(int)8" ! rtppcmadepay ! alawdec ! alsasink

Answer 1

You need to add the caps in receive, try the following pipeline:

gst-launch-1.0 udpsrc multicast-group=239.0.0.1 port=5004 caps='application/x-rtp, media=(string)audio, clock-rate=(int)44100, encoding-name=(string)L16, encoding-params=(string)2, channels=(int)2, payload=(int)96' ! rtpL16depay ! audioconvert ! alsasink