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Thread: Transcoder addon AAC LATM, does wowza support this codec for transcoding

  1. #1

    Default Transcoder addon AAC LATM, does wowza support this codec for transcoding

    Hi Guys,

    I am having problem transcoding a stream with aac latm as audio. HLS streams comes out without audio.

    2013-10-02	05:29:46	ECT	comment	server	INFO	200	-	LiveStreamPacketizerCupertino.handlePacket[SVorigin/_definst_/430]: Video codec:H264 isCompatible:true	-	-	-	4.662	-	-	-	-	-	-	-	-	-	-	--	-	-	-	-	-	-	-	-	-	-	-	-	-
    2013-10-02	05:29:46	ECT	comment	server	INFO	200	-	LiveStreamPacketizerCupertino.handlePacket[SVorigin/_definst_/430]: Audio codec:AAC isCompatible:true	-	-	-	4.663	-	-	-	-	-	-	-	-	-	-	-	--	-	-	-	-	-	-	-	-	-	-	-	-
    
    LiveStreamPacketizerCupertino.endChunkTS[SVorigin/_definst_/430]: Add chunk: id:5 mode:TS[H264,AAC] a/v/k:0/351/24 duration:11712
    
    INFO server comment - LiveStreamPacketizerCupertino.endChunkTS[SVorigin/_definst_/430_360p]: Add chunk: id:4 mode:TS[H264,NOAUDIO] a/v/k:0/360/3 duration:12012
    INFO server comment - LiveStreamPacketizerCupertino.endChunkTS[SVorigin/_definst_/430_3602p]: Add chunk: id:4 mode:TS[H264,NOAUDIO] a/v/k:0/360/3 duration:12012
    INFO server comment - LiveStreamPacketizerCupertino.endChunkTS[SVorigin/_definst_/430_720p]: Add chunk: id:4 mode:TS[H264,NOAUDIO] a/v/k:0/360/3 duration:12012
    Does wowza support this AAC format?

    Regards,

  2. #2
    Join Date
    Jul 2012
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    Default

    Hi,

    Yes, Wowza supports AAC audio. The issue here is that Wowza is not receiving audio packets from the source. Perhaps there is an issue with your encoder configuration?

    -Tim

  3. #3
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    As a follow up, I see that you are using mp4a-latm packetization. Take a look at this property which should resolve the issue: Property to change AAC packetization method:

    Wowza Media Server can output AAC audio using the mpeg4-generic and mp4a-latm (3gpp) packetization methods. The default packetization method is mpeg4-generic. To switch to mp4a-latm (3gpp), add the following property to the RTP/Properties container in [install-dir]/[application]/Application.xml (be sure to get the correct <Properties> container, there are several in the Application.xml file):

    <Property>
        <Name>audioPacketizerAAC</Name>
        <Value>com.wowza.wms.rtp.packetizer.RTPPacketizerMPEG4LATM</Value>
    </Property>
    -Tim

  4. #4

    Default

    Quote Originally Posted by tim_d View Post
    As a follow up, I see that you are using mp4a-latm packetization. Take a look at this property which should resolve the issue: Property to change AAC packetization method:

    Wowza Media Server can output AAC audio using the mpeg4-generic and mp4a-latm (3gpp) packetization methods. The default packetization method is mpeg4-generic. To switch to mp4a-latm (3gpp), add the following property to the RTP/Properties container in [install-dir]/[application]/Application.xml (be sure to get the correct <Properties> container, there are several in the Application.xml file):

    <Property>
        <Name>audioPacketizerAAC</Name>
        <Value>com.wowza.wms.rtp.packetizer.RTPPacketizerMPEG4LATM</Value>
    </Property>
    -Tim
    Hi Tim,

    Thanks for the reply, I have already set this audioPacketizerAAC property just to check if it might solve the problem we are having but the problem still exist. The streams are coming from SAT and being encapsulated into IP Multicast by our IRD as input for wowza, the format is mpeg ts SPTS. I have tried playing the streams coming from the IRD using vls and it recognized the audio without a problem.

    The streams might not be properly aligned but according to the changes in 3.6.2 patch 12, mpegtsVideoIsAligned and mpegtsAudioIsAligned are set to false by default. We are also transcoding this stream using wowza transcoder.

    I found this logs on the server:

    INFO server comment - JNI:TranscoderSession.audioDecoderCreate[_defaultVHost_:SVorigin/_definst_/430]: Create audio decoder: AAC: default
    INFO transcoder decoder-audio-start 430 {codec:AAC, objectType:SBR, sampleRate:44100, channels:2}
    INFO server comment - JNI:TranscoderSession.audioEncoderAdd[_defaultVHost_:SVorigin/_definst_/430:360p]: Create audio encoder: AAC: default
    INFO server comment - JNI:TranscoderSession.audioEncoderAdd[_defaultVHost_:SVorigin/_definst_/430:720p]: Create audio encoder: AAC: default
    WARN server comment - JNI:AudioDecoderAAC.decodeFirstFrame[_defaultVHost_:SVorigin/_definst_/430]: Decode failed
    WARN server comment - TranscoderWorkerAudioDecoder.handlePacket: Error audioDecoderDecodeFirstFrame: 4294967295
    Somehow it's failing to decode the audio streams


    Regards,
    Last edited by f.hernandez.b; 10-03-2013 at 09:49 AM.

  5. #5

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    anyone?

  6. #6
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    What is the source? I think Tim's first suggestion was going in the right direction: Wowza is not getting the audio from the source. The packetizing method is for the outgoing stream rtsp stream.

    Does the un-transcoded stream from Wowza playback in Flash RTMP client? Does it playback in VLC over RTSP? What do you see in VLC Tools > Codec info? And can you play the source in VLC, and what does Tools > Codec info say in that case?

    Richard

  7. Default

    We face similar problem
    in our scenario we have H.264/AAC source channel comming from SAT. we stream this channel via our IRD (dvblast) as a source for wowza.

    Signal -> IRD -> MPEGTS over udp -> wowza

    VLC show that audio codec is mp4a
    ffmpeg show that audio codec is latm_AAC
    wowza logs show thar audio codec is AAC

    VLC can play video and audio (everything is OK)

    but after wowza we have no audio. either using transcoder or not (pass-through audio).

    depacketization which is used by wowza is : MPEGTSDepacketizer which detect audio stream and show audio stream id (PID) properly.

    we are doubtful to aac_latm in audio source. another clue to this is when our input channel audio has not latm filter and it is pure AAC everything works fine.
    maybe wowza didn't use appropriate depakcetizer for MPEGTS udp input stream.

    would you please help us

  8. Default

    Hi
    we face similar problem too.
    when incoming signal (from SAT) uses aac_latm for its audio we get no audio after wowza, either using transcoder or not.
    the scenario is described here:
    Signal from SAT -> IRD -> MPEG-TS over udp -> wowza -> restream (with transcode) to other formats.

    MPEG_TS stream before wowza is playable in VLC and audio codec is mp4a (video codec is H.264)
    also with from ffmpeg we know that audio codec is latm_aac

    we are doubtful of latm filter, because when incoming audio is pure aac whole scenario works perfectly.
    it is not matter of Packetizer it is about DePacketizer (for incoming stream)
    also another usefull information is that in wowza detect an AAC stream and use MPEGTS DePacketizer for that.
    but maybe there should be an AACLATMDePacketizer or MP4ADePacketizer in wowza for this kind of audio stream.

  9. #9

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    Hi all,

    We are having exactly the same issue with exactly the same setup (HD stream from satellite).

    Did anyone manage to fix this issue?

    Our exact stream details from the sat feed are (from ffprobe):

    Stream #0:0[0xc9]: Video: h264 (High) ([27][0][0][0] / 0x001B), yuv420p(tv, bt709), 1920x1080 [SAR 1:1 DAR 16:9], 25 fps, 25 tbr, 90k tbn, 50 tbc
    Stream #0:1[0xca](eng): Audio: aac_latm ([17][0][0][0] / 0x0011), 48000 Hz, stereo, fltp

    Video is being transcoded with no issue but audio is having issues to be decoded.

    Thx,
    Isaac.

  10. #10
    Join Date
    Dec 2007
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    Isaac, and Yee,

    We would need to take a closer look, and need access to the source, or a recording of it. Open a ticket by writing to support@wowza.com. Include a link to thread for reference.

    Richard

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