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Basic Media Handling

Learn how to record, play back, and control media in VidRedi.

Recording a Channel​

What is a Recording Channel?​

In VidRedi, a "recording" or capture channel can be any of the following:

  • Baseband/Capture Card: Direct input from Blackmagic DeckLink devices
  • Network Streaming: RTMP, RTSP, SRT, or other network video sources
  • Download Channels: HLS (HTTP Live Streaming) sources

Each type of recording channel captures video in its own way, but all recordings are managed through the unified media library.

How Recordings Are Saved​

Transport Stream Processing​

VidRedi has an encode-once philosophy, in that the first time the video is encoded at the encoder it should then be saved in that format for decoding once. While this can come with its own challenges, it allows for easier storage of content already encoded. This means that we generally recommend MPEG-TS Streams be transmuxed to Matroska (.mkv) format, providing:

  • Easier playback compatibility
  • Better time-slipped recording support
  • Better support for seeking
  • Maintains original quality of the encoded stream

Starting a Recording​

  1. Select the Channel

    • Click on the channel you want to record
    • Ensure the channel is active and receiving signal

  2. Verify Source

    • Check that video is visible in the preview
    • Verify audio levels if applicable
      • Audio Level Meters: Real-time audio meters display on the right side of each channel card
      • Channel Selection: Click on individual audio meter bars to listen to specific channel pairs via WebRTC
      • Visual Indicators: Selected channels show a ring around the channel
      • Level Display: Each meter shows its channel number and current dB level in the tooltip

  3. Start Recording

    • Click the "Record" button
    • The interface will indicate recording is active
    • A new package will be created in the library

  4. Monitor the Recording

    • Watch for the recording indicator
    • Monitor disk space usage
    • Check for any error messages

Stopping a Recording​

  1. Click Stop:

    • Use the stop button in the channel interface
    • Confirm the recording has stopped

  2. Verify Recording:

    • Check that the package appears in the library
    • Verify the recording duration is correct

Download Channels (HLS)​

HLS download channels work differently from live capture.

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HLS downloads are still in a testing phase and there are some known issues that are still being worked through:

  • Downloads that have a lot of prior data can be loaded and the pipeline then stall due to not refreshing the current playlist file quickly enough.
  • Playback sometimes cannot start on every load.
  • Playback sometimes starts at the end of the file ("live") on load.

How HLS Downloads Work​

  1. Configure the HLS Source

    • Enter the HLS manifest URL (.m3u8)
    • Set quality preferences if multiple streams available

  2. Start Download

    • Initiate the download process
    • The system fetches video segments from the HLS source

  3. Progress Monitoring

    • Track download progress in the interface
    • Downloads continue in the background

  4. Completion

    • Downloaded content is automatically added to the library
    • Files are processed and ready for playback

HLS Download Considerations​

  • Network speed affects download time
  • Live HLS streams are downloaded as they become available
  • VOD (Video on Demand) HLS content downloads the complete file

Playing a Recording While It's Being Written​

One of VidRedi's powerful features is the ability to play back recordings that are still in progress.

Time-Slip Playback​

Time-slip allows you to:

  • Rewind live video while recording continues
  • Review recent content without stopping the recording
  • Jump to any point in the recording so far

Using Time-Slip:​

  1. Start Playback on Active Recording:

    • Select a channel that's currently recording
    • The playback will show the recording in progress

  2. Rewind:

    • Use the timeline or keyboard controls to go back in time
    • The recording continues even while you're watching earlier content

  3. Return to Live:

    • Jump back to the live edge
    • Or let playback catch up naturally

Playback Limitations During Recording​

While playing back an in-progress recording:

  • You can only play back content that has been written to disk
  • The furthest you can advance is the current recording point
  • There will be a small buffer delay between live and available playback; while you can decrease this time, there is a risk of stalled or failed playback if close to the edge of the recording

Using Transport Controls​

Transport controls allow you to navigate and control video playback with precision.

Selecting a Channel​

  1. Channel List

    • View all available channels on the Dashboard
    • Active channels show current status

  2. Click anywhere on a channel to make it active, indicated by a highlighted border.

  3. Channel Status Indicators

    • Starting: Channel is actively trying to start the pipeline, usually this happens relatively quickly but can take time depending on the source
    • Recording: Channel is actively downloading, capturing, or awaiting a stream source to become available
    • Stopped: Playback has stopped/paused
    • Playing: Channel is currently playing
    • Shutting down: Pipeline is ending and things are being cleaned up; this process can take several seconds
    • Idle: No special indicator

Playback Controls​

Basic Controls​

  • Play/Pause: Start or pause playback
  • Stop: Stop playback and return to the beginning
  • Timeline Scrubbing: Click or drag on the timeline to jump to a specific time
  • Jog Controls: Play at different speeds (0.5x, 2x, etc.)
Keyboard Shortcuts

VidRedi supports the following keyboard controls:

  • Space: Play/Pause
  • Left/Right Arrows: Video step backward/forward, modifiers:
    • Shift: 5 second step
    • Shift + Option / Alt: 30 second step
  • Home/End: Jump to beginning/end
  • D: Show debugging information overlay for the current channel

Debugging Information (D Key)​

Pressing D on a selected channel displays:

  • Pipeline stats
  • Network statistics (for streaming channels)

This information is valuable for troubleshooting basic issues.

Audio Monitoring​

VidRedi provides real-time audio level meters for monitoring and selecting audio channels.

Audio Level Meters​

Audio meters are displayed on the right side of each channel card and update in real-time (every 250ms):

  • Visual Design: Color-coded gradient bars (green → yellow → red)
    • Green (0-63%): Safe audio levels
    • Yellow (63-83%): Elevated levels
    • Red (83-100%): Peak/danger levels
  • Channel Labels: Each meter displays its channel number (1, 2, 3, etc.)
  • Tooltips: Hover over a meter to see the channel number and current dB level
Audio Meters Follow The Mix Matrix

Each output channel can have its own mix matrix. The meters follow what is being sent to the channel.

Click-to-Listen Monitoring​

The click-to-listen feature is used to route the selected channel pair to your browser. This allows you to monitor specific audio tracks without affecting the recording. Audio is always sent for the currently selected pair. Select which audio channel pair to monitor:

  1. Click a Meter: Click on any audio meter to listen to that specific channel pair. Click the currently selected pair again to mute.
    • Meters are displayed per individual channel (1, 2, 3, 4, etc.)
    • Clicking any channel within a stereo pair selects that entire pair
  2. Visual Feedback: Selected channel pairs display a highlighted ring
  3. Audio Routing: The selected stereo pair is always routed to your browser
    • Clicking a different pair switches to that pair
    • The system always sends audio for the selected pair

Timeline Navigation​

The timeline shows:

  • Total recording duration
  • Current playback position
  • Recording progress (for active recordings)

Using the Timeline:

  • Click anywhere to jump to that position
  • Drag the playhead for precise positioning