Wrong codec when publishing through RTSP

[Baptiste]

Hi,

Sometimes, when publising in RTSP, Wowza does not recognize correctly the codecs.

My workflow is the following : I have a H264/AAC stream that I transcode and republish to Wowza with gstreamer in VP8/OPUS, using RTSP/UDP.

That is :

stream1 (H264/AAC) —RTSP/UDP—> gstreamer transcode —RTSP/UDP–> stream2(VP8/OPUS)

But sometimes, the audio or video of the stream2 does not want to play (with a webrtc player or VLC). In those cases, the log file tells me that the codec found in stream2 is H264 or AAC instead of VP8/OPUS.

For example :

LiveStreamPacketizerCupertino.handlePacket[live/definst/stream2]: Video codec:VPX LiveStreamPacketizerCupertino.handlePacket[live/definst/stream2]: Audio codec:AAC

or

LiveStreamPacketizerCupertino.handlePacket[live/definst/stream2]: Video codec:H264 LiveStreamPacketizerCupertino.handlePacket[live/definst/stream2]: Audio codec:OPUS

But the stream does contains VP8/OPUS, as the SDP exchanged between Wowza and Gstreamer tells so :

…

m=audio 0 RTP/AVP 96

…

a=rtpmap:96 OPUS/48000/2

…

m=video 0 RTP/AVP 98

…

a=rtpmap:98 VP8/90000

…

Do you have any clue about this ?

Thank you,

Ben

[Rose_Power-Wowza_Com]

Thanks for reaching out @Baptiste. With webRTC playback the audio does need to be transcoded to Opus (as one option) and you show you did that.

I don’t have any specific Wowza docs to share with you for gstreamer, but I did see a few people have had an issue getting Wowza to read what’s inside the gstreamer package. On Stack Overflow, someone did share a solution that worked for them and they disabled security settings to ensure the gstreamer is compatible and can be read.

I hope this link helps:

https://stackoverflow.com/questions/41550901/how-to-stream-via-rtmp-using-gstreamer

[Rose_Power-Wowza_Com]

I saw this solution as well in Google search. Please let me know if either of these work:

http://gstreamer-devel.966125.n4.nabble.com/Need-Help-to-send-GStreamer-H264-AAC-packets-to-Wowza-Streaming-Engine-td4681972.html

[Baptiste]

Thank you for the answer.

Actually, gstreamer has no problem streaming H264/AAC stream to Wowza through RTMP. But I do need to transcode the stream to VP8/OPUS, and the only way to stream VP8/OPUS to Wowza is through RTSP.

Most of the times, it works correctly. But sometimes, Wowza does not seem to recognize correctly the codecs, and tells me what i’m pushing is H264/AAC while it is VP8/OPUS.

[Rose_Power-Wowza_Com]

Thanks @Baptiste, I appreciate that feedback. Our tech support team would like to take a look at more closely for you and and run some tests. Would you able to submit a support ticket so we can further assist? I think this would help us best replicate your scenario and determine the cause.

Open a Support Ticket | Wowza Media Systems