In a recent article by David Thomas, he looked at 3 different remote recording services, which are becoming more and more important for the industry during the current COVID-19 situation. Having read it community member Erik Gierich commented that he uses SessionLinkPRO and so we asked Erik if he would share his experiences of using SessionLinkPRO and here is his article. Over to you Erik…
Unlike the UK and US here in Germany ‘real’ ISDN has been shut down for some time now but the emulated ISDN that replaced real ISDN lines wasn’t as stable as everyone had hoped.
The alternative solutions like Source Connect and connections via SIP/RTP (for example with the Maya Centauri) that have been around for quite some time aren’t cheap and, for some, the setup can be frustrating. The owner of SessionLinkPRO, Tim Proegler, saw his opportunity and developed his own product. I have been using SessionLinkPRO for several years now in different studios to record voice talent and this article is based on my experiences with the service. I’ll try to explain exactly what SessionLinkPRO is, what it can do, how to use it and give you some tips to help get a smooth connection.
What Is SessionLinkPRO?
SessionLinkPRO (or SLP) is a browser-based remote recording, video and conferencing solution. There are three services offered by SessionLinkPRO:
SessionLinkPRO Recording is used to record up to two remote signals
SessionLinkPRO Video is a free add-on to SLP Recording that features bi-directional video transmission (no audio)
SessionLinkPRO Conferencing is a separate service that offers a conferencing solution for up to four clients to listen to and direct a recording session.
The only things necessary to establish a connection are a Chrome-based Browser (Chromium, Google Chrome, Opera or Yandex) on both ends and a stable broadband internet connection.
You will also need to sign up for an account. There is a free 7-day trial available so you can try it out before you commit to a subscription.
SessionLinkPro Recording
As the name suggests SessionLinkPRO Recording is tailored for recording situations. The host (studio) starts a session and invites up to two guests with a link that includes the connection settings so that the guest doesn’t have to worry about them. In my experience, this comes in handy with most voice talent artists, because they don’t want to have to deal with these settings and often don’t know even what they mean.
The service uses the WebRTC technology. The audio codec used is the OPUS codec with up to 256kbit/s mono or 320kbit/s stereo. SLP Recording offers connections in Mono, Dual Mono (with two guests) or stereo.
To start a session go to the SessionLinkPRO website and click start session link and recording. Log in with your credentials and after allowing Chrome to access your Audio and MIDI devices the session starts.
Choose your Audio Input and Audio Output Device and if you want to use MIDI you can also select the MIDI Input - but more on that later.
You can now invite guests by clicking on Create Session Link and filling out the details. In this window, you can configure the settings that the guest will use to connect with you. You can have up to 256kbit/s for a mono connection or 320kbit/s for a stereo connection. You can then copy the link or send it directly from SLP.
If you copy the link you can also change the settings in the URL. The first part before the comma is your username, the second is the Channel type (where 0 is mono and 1 is stereo) and the last part is the bitrate in bit/s. For example, “….php?username,1,320000“ would be a stereo connection with the user username and a bit rate of 320kbit/s.
As soon as a guest has opened the link in his Chrome-based browser and entered a name, he pops up under Available Connections and you can start a text chat if that helps. You can remove the user by dragging them from the Available Connections list to the Remove User field or establish a connection by dragging the name from the Available Connections list onto a free Connection field and then clicking connect next to the name. As you can see there are only two Connection slots available and 2 guests plus the host is the maximum that SessionLink Recording can handle. SessionLinkPRO doesn’t have password protection for connections but it doesn’t need one, because it is the host that controls who to send invites to and who to connect to from the Available Connections. This means you can use the same link for different sessions as long as you want to use the same settings.
Recording Audio
You can record all of the signals via SessionLinkPRO. In your Chrome-based browser, you can choose if you want to record the local signal, the remote signal, or both of them. Depending on your setting you will get either a 1, 2 or 4-channel WAV file at 48kHz/16Bit. The guest has the same choice for his recording so that you can have a backup recording of your session on the remote machine.
If you want to record directly into your DAW you have to do some routing to get signals in and out of your DAW. There are a couple of ways to do that:
Get in and out of your interface via hardware if you can choose it in your DAW and in Chrome at the same time. In my experience, this is possible with most interfaces on a Mac and on Windows if they support ASIO and WDM.
Use a second interface for SLP and connect it to your primary interface. This is necessary if you are using Pro Tools HDX, because you can’t use it in another application as soon as Pro Tools is running.
Use a loopback function of your interface (i.e. RME TotalMix)
Use a software loopback application such as Loopback from Rogue Amoeba
Using MIDI with SessionLinkPro Recording
SessionLinkPRO Recording offers the ability to send MIDI from the host to the guest but only one way. This function is most commonly used to send MTC to sync to picture. You can sync two studios or if you are connected directly to a voice artist they can open a video in an application like Video Slave or Horae and can see the picture in sync to your DAW.
If you are sending MTC via the MIDI connection, the guest can open a TimeCode Reader in the SessionLinkPRO window to check that they are receiving the timecode correctly. This is really useful when checking connections and finding MIDI routing errors.
To get MIDI out of your DAW and into SessionLinkPro and the other way around on the Guests end of the connection, you have several options:
Use an internal software MIDI connection. macOS comes with the IAC driver that enables this and can be configured and activated in the Audio-MIDI-Setup. For Windows, there are apps like virtual MIDI.
Create a MIDI Loopback on your interface. Take a MIDI cable and plug it in your interfaces MIDI in and MIDI Out.
Use a second interface and Plug the MIDI Out in the MIDI in of your primary Interface or vice versa
Make sure that the synchronisation settings Generator/Reader and Frame rate) in your DAW/video playback app are set correctly.
If your DAW can only create or read LTC there are apps like Horae from Sononum to translate to/from MIDI. Or you can do it the old fashioned way and send the LTC on the right channel.
SessionLinkPro Video
If you don’t have the ability to send/receive MTC or LTC, then an easier way is to use SessionLinkPro Video to send out the video directly. SessionLinkPRO Video is a free add-on that provides bi-directional video transmission. It runs in its own browser tab or on a second computer. With a capture device (like a Blackmagic Intensity or equivalent) you can stream your production video to the remote computer. This is useful for recording voice artists in sync with a video or even for ADR sessions. If necessary you can also use it with a webcam. You can use it in normal mode, full-screen mode, or detach the video window to scale and position it as you like.
Starting a session is as easy as starting an SLP Recording session. Go to the SessionLinkPro website, choose start session link, click on video and log in with your credentials. Choose your video device and (if supported by the driver) the Resolution and Bitrate. You can select every Webcam or video device that is connected to your machine or after installing the SessionLinkPRO Chrome add-on, even share your screen.
You can now, either enter a session name or create a random name. Like SLP Recording, SLP video doesn’t have password protection, but you can create a unique session name for every session.
With a click on Start Session, the session begins. Inviting participants works the same way as it does with SLP Recording with the only difference being that the link is always different depending on the session name.
Your guest can see your video as soon as they connect and you can see their’s if they choose to send one.
SessionLinkPRO Video Observations
My experience with SLP video has shown that it isn’t perfect for recording to picture, because it isn’t always in sync to the audio and can be off by a couple of frames compared to the audio stream. This might be good enough for a voiceover, but not for ADR. I believe it has to do with the time it takes to encode/decode the video compared to the audio. If you have to record in sync a lot then I recommend using MTC option (see above) to sync your DAWs and video players.
SessionLinkPro Conferencing
The name says it all - SessionLinkPro Conferencing is designed for teleconferencing. You can send audio and video at the same time. It also offers a group text chat for all connected users.
The quality of the connection doesn’t seem to be as good as it is with SLP Recording, you can’t record in SLP Conferencing directly and you don’t have separate channels for every participant. So if you want to do a remote recording I would recommend using SLP Recording instead of SLP conferencing. It is ideal if you are making a recording session and your clients want to listen to the session and direct with better sound than skype or a phone connection.
To start a session go to the SessionLinkPRO website and click start session link and conferencing. You are now asked to choose your Audio In and Out and your Video Source. Be sure to set it right, because you can’t change it once the Conference has started. This is also the time to enter a conference name and a password.
Click Start Conference to start the session. Inviting participants works the same way as with SLP Recording and Video. The link contains the conference name you just entered.
If a client doesn’t have the ability to use the Chrome-based browser (i.e. they aren’t allowed to install apps on their work computers), SessionLinkPRO Conferencing offers the feature to enter the credentials of a SIP (Session Initiation Protocol) account in your SLP account settings so that a client can join the conference by calling your SIP phone number or you can call them directly from SLP Conferencing. In the SLP account settings, you can also customise the look of your SLP conference.
SLP Conferencing has a push-to-talk option and audio processing built in that are designed to prevent feedback and echoes, that you can switch off if you want to.
You can have up to four clients connect to your SLP conferencing session.
Tips For A Stable Connection With SessionLinkPro
Have a good internet connection ;)
Use a LAN connection on both ends instead of Wi-Fi
Try not to have Uploads or Downloads running in the background
On some routers, you can prioritise real-time services - do that if you can.
If you are using SLP video on top of SLP recording make sure your and your partners connection can handle the video bitrate and adjust it accordingly.
Screen sharing can decrease your machine’s performance and can be unstable. In my experience, it is better to split your monitor signal and use a capture card like the Blackmagic Ultra Studio Mini recorder.
If your connection isn’t stable or you can’t establish a connection at all, try disabling IPv6 connection. This is done by clicking on the button with the two arrows on it. In SessionLinkPro Conferencing it is in the bottom left-hand corner in the Conference Setup window.
Dropouts and Statistics
As the connection is made via the Internet, packets can be lost, which can result in audio dropouts. You can also see them in the waveform because most times they manifest themselves as a short period of digital silence. If you want to check your connection and have statistics for it there is a neat little feature that Chrome offers.
SessionLinkPro and Source-Connect Now both use the WebRTC technology to connect. Chrome offers extensive statistics for every WebRTC connection. You can access them in Chrome by using this link in your Chrome browser.
You can see the number of Lost packets of your guests connection under the section… “RTCInboundRTPAudioStream“ and even see a graph under “Stats graphs for RTCInboundRTPAudioStream“.
Pricing
Only the host (studio) needs an active account. Guests are always free.
It is a subscription service with the shortest period being one month. The prices for SessionLinkPRO vary slightly due to exchange rates, but here in Europe, they are…
SessionLinkPro Recording (including SLP Video) - 20€/month (ca. 18£/22$) excl. VAT
SessionLinkPro RConerferencing - 20€/month (ca. 18£/22$) excl. VAT
There are discounts if you choose to pay for 6 or 12 months in advance. For example, 12 months is 200€
There is also a free 7-day trial account available.