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Transcoding

Vindral offers a range of transcoding options to ensure that your content is delivered in the best possible quality to your viewers. Most streams sent over the internet use multiple qualities to cater to different viewer conditions. Often, a single stream is sent to our service and turned into multiple qualities, a.k.a. an ABR Ladder.

This process is called Transcoding.

Our transcoding components are built for robust live 24/7 streaming and support many different codecs and settings. These are used internally within Vindral and can be used on-prem as well. Let us know if you are interested in learning more.

Why transcoding is important​

If you are streaming to a global audience, you need to ensure that your content is delivered in the best possible quality to your viewers. If your source is a high-quality 4K stream, it is important to transcode the stream into multiple bitrates and resolutions to ensure that your viewers can watch your content without buffering. The Vindral player automatically selects the best quality based on the viewer's network conditions and device capabilities, this is called Adaptive Bitrate or ABR.

With our transcoding, we support new efficient formats such as AV1 that can save up to 30% of bandwidth compared to H.264. By reducing the bandwidth and keeping the quality high, you can reach more viewers with less resources.

All transcoding is done in real-time, and we ensure that your content is delivered in sync on all qualities and devices.

Adaptive Bitrate (ABR)​

Vindral supports Adaptive Bitrate (ABR) streaming, which allows us to deliver the best possible quality to your viewers based on their network conditions. ABR streaming is achieved by encoding your content at multiple bitrates and resolutions, and then delivering the best possible quality to your viewers based on their network conditions.

Transcoding profiles​

A transcoding profile is a set of rules that define how a stream is transcoded. Both the audio and video can be passthrough and/or transcoded into other formats. Some settings that can be included in a transcoding profile are:

  • Bitrate - the amount of data that is transmitted per second.
  • Resolution - the number of pixels in each dimension, e.g. 1920x1080. Or a scale factor, e.g. 50% for half the resolution of source.
  • Frame rate - the number of frames per second.
  • Codec - the format used to encode the video and audio data.
  • Thumbnail - an image of the video source. How often the thumbnail is updated and in which qualities it is available.
  • Deinterlacing - converting interlaced video into a non-interlaced form.
  • Frame rate conversion - converting the frame rate of a video.
  • Passthrough - no transcoding of the video or audio data to keep the original quality.
  • Crop - removing parts of the video frame.
  • GOP Alignment - aligning the Group of Pictures (GOP) based on the passthrough stream.

We provide one default transcoding profile, but we can create custom transcoding profiles to suit your specific needs.

Example transcoding profile​

As an example with an RTMP ingest with AV1 in 1080p at 4 Mbps. From the one incoming stream, we can create these outgoing streams:

  • 1080p (1920x1080) - 4 Mbps, AV1 (passthrough)
  • 1080p (1920x1080) - 4.5 Mbps, H.264
  • 720p (1280x720) - 2 Mbps, AV1
  • 720p (1280x720) - 2.5 Mbps, H.264
  • 360p (640x360) - 0.4 Mbps AV1
  • 360p (640x360) - 0.6 Mbps H.264
  • Audio - 128 kbps, AAC passthrough
  • Audio - 96 kbps, Opus
  • JPEG Thumbnail (1280x720) - updated every 5 seconds
  • JPEG Thumbnail (640x360) - updated every 5 seconds

The incoming stream can be passthrough without transcoding to avoid quality loss, and additionally, the stream is transcoded into multiple bitrates and resolutions to allow viewers with different network conditions to watch the stream without buffering. In this example we also create a H.264 stream for compatibility with older devices. Notice the higher bitrate for the H.264 streams to keep similar quality as the AV1 stream.