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Airtime hangout #3 - recording in Airtime
  • Hey everyone, 

    this is turning into a regular thing now - we're going to run another Airtime hangout with the developer team on Thursday, 22nd August: 11am Toronto time, 5pm Berlin time. 
    As usual, please stay keep an eye on this post for the link to the live stream (seems like we only can create a link just before the live event, we're working on a solution...). 

    This time we're going to focus on everything around (live)recording inside/outside Airtime. We'd like to hear how about your setup - what is working great, what are the issues? And of course: what can we make better? Come and join us in the hangout and demo/contribute/ask/support! 

    Feel free to start the conversation already here - so we can prepare for the next hangout :) 

    And to make sure you won't miss out of our next hangouts, you can also subscribe to our Sourcefabric event calendar (Google calendar): 

    Looking forward seeing you all there! 

    Best, 
    Lisa. 

    P.S. Here's the link to the live hangout:




    Post edited by Josh McLain at 2013-08-22 12:04:24
    Airtime Lead
    Head of Products at Sourcefabric
    *-*
  • 26 Comments sorted by
  • OK, here are my recommendations:

    1. Allow record flag to be set (and changed) independently of show content.
    2. Provide a user definable option for where to record from: either a) stream or b) analog input
    3. Implement analog input pass through as a scheduled block, similar to a webstream.

    Nat
    100.3 FM in Waterloo, ON, Canada
    www.soundfm.ca
  • Vote Up0Vote Down BartBart
    Posts: 89Member
    tnxxxxxxxxxxxxx
    Schelstraete Bart - http://www.contact-dance.com
    image
  • I may not be able to attend the hangout but I wanted to add my thoughts here.

    In my setup, I have an analog mixer in a traditional studio. The output of the mixer (program audio) gets split to: 1) studio to transmitter link 2) Airtime input. I also have Airtime as on of my sources on the mixer so that I can mix any audio from Airtime with other sources. I will not be using Airtime's output stream other than to send it to the analog output.

    What I Want
    I want to set up my shows in Airtime and have the record flag set for all of them. Sometimes shows will be live analog using laptop and microphone connected through the mixer. At other times, a host may stream into Airtime from her home studio, or schedule a playlist in Airtime remotely. During Airtime playback, it's audio will go through the mixer and the program audio will go back into Airtime for the recording.
    100.3 FM in Waterloo, ON, Canada
    www.soundfm.ca
  • Vote Up0Vote Down Albert FRAlbert FR
    Posts: 1,978Member, Airtime Moderator
    Post edited by Albert FR at 2013-08-13 04:20:00
  • The problem with that solution is that you then need to maintain 2 calendars, one in Airtime and one in the Stream ripping program.

    Stream ripping is not required. All that is required is to enable Airtime to record and play analog audio simultaneously. Currently, this is disabled and I don't understand why. Per the manual, you can't record a show that contains content.
    100.3 FM in Waterloo, ON, Canada
    www.soundfm.ca
  • Vote Up0Vote Down Albert FRAlbert FR
    Posts: 1,978Member, Airtime Moderator
    I'm agree with you, but for now it is a solution
    that's a feature asked since a long time ago...
  • So what is the reason for the current limitation? This appears to be not a bug but an intentional design feature.
    100.3 FM in Waterloo, ON, Canada
    www.soundfm.ca
  • Vote Up0Vote Down Albert FRAlbert FR
    Posts: 1,978Member, Airtime Moderator
    it's only not implemented yet
    but recording a show is not mandatory
    a stream (from master or show source) recorded  will be for some of us a real great feature (for replay)
    perhaps available on 2.5 or 2.6...
  • Right now Airtime can record from the line input. It can also schedule playback to the line output. Those capabilities are present and fully implemented. However, it seems like an extra check has been put in place to not allow both to occur at the same time. The manual mentions that you cannot do both with no explanation as to why. Is there some technical problem with doing both?

    My understanding of a scheduled program is that there is a database record that stores each program. One of the fields is record_enabled? If that is set to yes, then Airtime won't allow content and also won't allow changing the flag either. What would happen if Airtime did allow those things?

    What is the intention of the record feature in it's current state? If this is half done, then why does the manual make it sound like the current state is the way it should be?

    I am really interested to hear from the developers on this. Thanks.
    100.3 FM in Waterloo, ON, Canada
    www.soundfm.ca
  • Vote Up0Vote Down hoerichhoerich
    Posts: 627Member, Airtime Moderator

    Right now Airtime can record from the line input. It can also schedule playback to the line output. Those capabilities are present and fully implemented. However, it seems like an extra check has been put in place to not allow both to occur at the same time. The manual mentions that you cannot do both with no explanation as to why. Is there some technical problem with doing both?



    I think it has to do with eca, not with liquidsoap. But that's just speculation.

    Generally I was also expecting a different behaviour than Record&Rebroadcast currently works.
    We did have a lot of discussions about this, just to tease a little.
    http://forum.sourcefabric.org/discussion/11050/live-show-from-line-input-not-streaming/p1
    http://forum.sourcefabric.org/discussion/15251/line-in/p1
    http://forum.sourcefabric.org/discussion/15583/line-in-as-a-live-source/p1

    As we run Airtime at an FM-Radio Station with local Live-Studio, I am still a big supporter of Mulitple-Line-Inputs.
    For me it's essential for near future!
    Next
    week I try to encourage a few devs from a friendly RadioStation near
    ours, to also jump on Airtime and help developing Live-Line-In-Support.
    They won't jump on Airtime without this feature.

    I will demo our Showcase during the next hangout. But Nat, you already know my setup...
    Official Airtime Forum Manager
    --------------------------
    Most of the time an issue is located between keyboard and chair.
  • Vote Up0Vote Down Albert FRAlbert FR
    Posts: 1,978Member, Airtime Moderator
    A good point hoerich
    But as you Said, you're using airtime as a radio station
    But a lot of users are webradios :-)
  • Vote Up0Vote Down Daniel JamesDaniel James
    Posts: 844Member, Sourcefabric Team
    The original use case for the current recording feature was an FM station that was not streaming via Airtime, rather using it as a timed recording/playback system. It uses the default ALSA device, which potentially blocks the use of this device for a simultaneous stream input (unless a sound server or ALSA plugin is used).

    There are three ways I can think of improving the situation...

    1. Have an ALSA plugin split the hardware input into two virtual devices, one to be used by Liquidsoap for pass-through streaming and the other for the recorder process

    This offers a potential solution but it is hard to guess what kind of soundcard the user has (if any), and which ALSA options are available for it, so it may be hard to auto-configure. Also it does not help record shows that are generated from the Library.

    2. Have the recorder use a stream ripper on the output, and leave the hardware input free for pass-through streaming

    It may seem strange to create a stream for a station which is not streaming to the Internet, just so that shows can be recorded, but we probably want to do lossy compression anyway (to keep the disc space required for the recordings reasonable).

    Possibly you would want to use a higher bitrate for the stream meant for ripping, or even stream in FLAC for recorder use only (i.e. a lossless stream which you might not advertise to the public). 

    3. Make a small change to the recorder script so that it uses the
    ALSA device specified in a configuration file, rather than the default
    device

    This is very easy to do but it requires multiple ALSA devices or one multi-channel device plus some external routing, such as a mixer. Like option 1, it does not help record shows that are generated from the Library.

    So personally I favour option 2, using a stream ripper instead of Ecasound, even when that stream is on the localhost only. It would mean removing the prohibition on adding content to shows set for recording. Also we could use more of the metadata from the show to tag the recording better.

    I like the suggestion of having a global recording preference so that the user does not have to specify each show for recording. We would probably need a preference such as 'Delete recorded shows after x days' to prevent disks filling up.
  • Vote Up0Vote Down Albert FRAlbert FR
    Posts: 1,978Member, Airtime Moderator
    I'm totally agree with you @daniel :D
    Point 2 is the solution for everybody
  • Vote Up0Vote Down hoerichhoerich
    Posts: 627Member, Airtime Moderator

    Albert FR said:

    I'm totally agree with you @daniel :D
    Point 2 is the solution for everybody



    Would it be possible in case 2 to use multiple Inputs?
    For sure not simultanously, but just to be able to connect two or more studios to Airtime-Server-Soundcard. (M-Audio 1010 in our case)

    For me 320kbps-mp3-files would last for Recordings. Being able to use WAV or FLAC would be cool but not essential.

    The "Delete Recordings after X Days"-Feature would be nice.
    I already ticketed a similar request for files http://dev.sourcefabric.org/browse/CC-5304
    Official Airtime Forum Manager
    --------------------------
    Most of the time an issue is located between keyboard and chair.
  • Vote Up0Vote Down Albert FRAlbert FR
    Posts: 1,978Member, Airtime Moderator
    with liquidsoap you can do that (have multiple inputs)

    but effectively that's not implemented in airtime for now

    flac is less destructive than mp3 the bass and treble are more respected
  • Thanks for the perspective @Daniel.

    I think for internet radio users, who are essentially using Airtime for what it was made for, this whole recording issue gets solved by a stream-ripper that can be scheduled by the calendar.

    For FM users, Airtime can be set up in different positions in the analog chain. It can be before the mixer (my case) or after the mixer (Hoerich's case). In either case, program audio (the final mix) needs to get to the recording.

    Pre-mixer
    Airtime is used as a recorder and program audio from the mixer comes in through the analog input, so we just schedule the recording via the calendar. Since Airtime is pre-mixer, scheduled content in Airtime will be played at some point through the mixer and this needs to be recorded too, so we can't restrict recording for only no-content shows. I am assuming that Airtime would be able to able to use the ALSA input and output devices simultaneously without any ALSA plugins or configuration files.

    Post-mixer
    Program audio is at the output of Airtime. The solution is the same as the internet radio case. The Airtime input in this case is not used because, currently, you can't play through.

    @Daniel, which case was assumed when the record feature was added?

    Is it not trivial to solve the Pre-mixer case?

    There are several factors affecting the decision to go pre or post mixer. It could be a whole other discussion and maybe it is relevant to this. An important goal is to have only one schedule that drives everything.
    Post edited by Nat Persaud at 2013-08-14 16:33:46
    100.3 FM in Waterloo, ON, Canada
    www.soundfm.ca
  • Vote Up0Vote Down hoerichhoerich
    Posts: 627Member, Airtime Moderator
    for me only the following is important

    If I select "Record from Line-In" in the preferences of a show, the Sound
    of the ALSA-Default-Input will be broadcasted to the audience and is
    recorded simultanously.

    http://forum.sourcefabric.org/discussion/comment/21533#Comment_21533

    If Airtime should really become the best radio automation software in the world (and it's on its best way ;-) ), it should also be suitable for FM-Stations.
    Official Airtime Forum Manager
    --------------------------
    Most of the time an issue is located between keyboard and chair.
  • @hoerich, why do you want the line input to be recorded? Don't you want Airtime's output to be recorded instead?
    100.3 FM in Waterloo, ON, Canada
    www.soundfm.ca
  • @hoerich, why do you want the line input to be recorded? Don't you want Airtime's output to be recorded instead?
    100.3 FM in Waterloo, ON, Canada
    www.soundfm.ca
  • Vote Up0Vote Down hoerichhoerich
    Posts: 627Member, Airtime Moderator

    @hoerich, why do you want the line input to be recorded? Don't you want Airtime's output to be recorded instead?



    I'm hoping for a Record-per-Show-Function.
    No matter where to touch the record. Technically it seems that it has to be done on the output.

    My wish for Record&Rebroadcast-Enhancements:
    Live-Broadcast & simultaneously record each Show from Line-Input with the ability to automatically schedule repeat(s) of the recording file.

    A 24/7-Record is secondary for our Station.
    Official Airtime Forum Manager
    --------------------------
    Most of the time an issue is located between keyboard and chair.
  • Vote Up0Vote Down Daniel JamesDaniel James
    Posts: 844Member, Sourcefabric Team
    Hi Nat, in the original recorder design, Airtime was more like a Tivo, being used to time-shift shows. It would use an aux send from the mixer to capture live content, and play it out to an aux return as a repeat show when the studio was unstaffed. There was no simultaneous capture and playout, so there were no issues with full duplex use of soundcards.

    In the proposed redesign of the recorder, we will probably need a recommended list of audio hardware if we rely on full duplex use. Liquidsoap can do full-duplex without a buffer (see the last example here: http://savonet.sourceforge.net/doc-svn/cookbook.html) but of course this is not strictly necessary if you have a mixer - you would just send the live audio direct to the transmitter, without latency.

    Even so, I would suggest that in an FM scenario, the recorder uses the stream output, rather than the ALSA device. This is because Liquidsoap has already done the CPU work of compressing the stream data, so we don't need to do that a second time in the recorder program. Even if there is no Internet, Airtime uses Icecast for browser-based monitoring (the Listen button), so the whole system could run on localhost if necessary.

    Lately I have been experimenting with icecream, a simple Perl script that takes an output stream and saves it as files, based on various parameters including time in minutes: http://packages.debian.org/en/stable/amd64/net/icecream

    Possibly we could reimplement the features of icecream that we need in Python, or just use it directly. The implication is that we need a fallback at the Icecast level to make sure the stream does not ever die (killing the recorder process), e.g. when a Liquidsoap parameter is changed and Liquidsoap is restarted. Happily, that would also help ensure that the listening public does not get disconnected either, so it's a win-win.

    Cheers!

    Daniel
  • We use the Airtime.Pro SaaS platform for our virtual radio station - Dakota Music Collective. Its a collection of 100% local/regional original music from the Dakota area in the US.  We are a nonprofit organization called Community Radio Group Broadcasting.  Website is www.crgb.us, and we have an Android App called Dakota Music Collective - hope you will check it out!

    We started in April this year and have done about 10 live shows, and Airtime.pro has performed flawlessly every time!

    We use a Yeti USB stereo condensor mic, and mix that with a line out from the house mixer. On a Macbook Pro, we use Ladiocast which is a fantastic little program that allows multiple audio sources to be fed to up to 2 stream outputs if necessary.

    We have also on ad-hoc occasions used an iRig iCast condensore mic connected to a Samsung NoteII smartphone, running an Android App called "Broadcast Myself". This also works quite well with Airtime.pro.

    These are the tools we use for live, and they have worked great for us so far!
    Thanks,

    -Lee McKenna, Founder
    Community Radio Group Broadcasting
    Sioux Falls, SD USA
    lee@crgb.us
    www.crgb.us

  • We're talking now! 

    Tune in here: 
  • SOX   http://sox.sourceforge.net/  for all your recording and audio processing and it can be scripted easily.

    Butt can be used for live and show recording
    Anyone reading this a find it funny about my grammar , I make no apology ,Go get a translator.
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    “Any intelligent fool can make things bigger, more complex, and more violent. It takes a touch of genius — and a lot of courage to move in the opposite direction.”
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    May the force be with you,until our path or destiny bring us in tandem.
  • Vote Up0Vote Down Albert FRAlbert FR
    Posts: 1,978Member, Airtime Moderator
    Sox is great, but as said into the hangout, an internal system recording would be great ;-)
  • Hi Nat, in the original recorder design, Airtime was more like a Tivo, being used to time-shift shows. It would use an aux send from the mixer to capture live content, and play it out to an aux return as a repeat show when the studio was unstaffed. There was no simultaneous capture and playout, so there were no issues with full duplex use of soundcards.

    Albert, thanks for your response. The Tivo idea clarifies a lot. Please
    note that I did not get that sense from reading the manual.
    In my case shows are typically live. But, I want to have the
    flexibility of doing scheduled play or streaming using the exact same
    schedule. For example, if a programmer can't make it one week or if they want to
    do a remote live to air, they should be able to do that at will without
    changing the schedule. In parallel, I want all shows to be podcasted
    automatically, which just means recording and tagging.


    In the proposed redesign of the recorder, we will probably need a recommended list of audio hardware if we rely on full duplex use. Liquidsoap can do full-duplex without a buffer (see the last example here: http://savonet.sourceforge.net/doc-svn/cookbook.html) but of course this is not strictly necessary if you have a mixer - you would just send the live audio direct to the transmitter, without latency.

    I'm not sure what you mean here. Can you comment on the question of pre or post mixer and which you are assuming? I think this is a critical point.


    Even so, I would suggest that in an FM scenario, the recorder uses the stream output, rather than the ALSA device. This is because Liquidsoap has already done the CPU work of compressing the stream data, so we don't need to do that a second time in the recorder program. Even if there is no Internet, Airtime uses Icecast for browser-based monitoring (the Listen button), so the whole system could run on localhost if necessary.

    Agreed.


    Lately I have been experimenting with icecream, a simple Perl script that takes an output stream and saves it as files, based on various parameters including time in minutes: http://packages.debian.org/en/stable/amd64/net/icecream

    Possibly we could reimplement the features of icecream that we need in Python, or just use it directly. The implication is that we need a fallback at the Icecast level to make sure the stream does not ever die (killing the recorder process), e.g. when a Liquidsoap parameter is changed and Liquidsoap is restarted. Happily, that would also help ensure that the listening public does not get disconnected either, so it's a win-win.

    Well I think it's fine to record what the audience heard even if it cut out, but you have a solution so good. It is vitally important that the user need only define the schedule once, not separately for record and playback.
    100.3 FM in Waterloo, ON, Canada
    www.soundfm.ca