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Understanding VoIP multi-codec transcoding
VoIP relies on codecs that permit the seamless connection between callers and networks. But there are many codecs and multiple endpoint devices. Enter VoIP multi-codec transcoding.
Voice over IP multi-codec transcoding switches codecs as VoIP network conditions change and, in the process, avoids encoding or format mismatches that can lead to dropped calls or low-quality video. The technique optimizes bandwidth even as it maintains enterprise-level audiovisual quality.
What is VoIP multi-codec transcoding and why is it necessary?
First, let's examine transcoding. Transcoding converts an encoded digital data file, such as an audio or video file, into another digital format so it can be transmitted to another network or device. If the target device is incompatible with the source, transcoding ensures the delivery of files in a format the target device can support. Transcoding is used across a variety of industries, among them media streaming, gaming, surveillance and enterprise communication.
VoIP multi-codec transcoding
In enterprise communications, VoIP transcoding is used for video conferencing, screen recording, group calling, media sharing, storage management and other important functions. Each device in a group call or video conference may rely on a different codec -- the voice encoding algorithm that enables the exchange of information between two VoIP endpoints. VoIP multi-codec transcoding converts the codecs underpinning these audio and video streams from one to another or to multiple codecs, enabling communication to take place.
Two VoIP endpoints can choose from a variety of codecs, among them G.711, G.726, G.729A, G.723.1 and CVSD, or continuously variable slope delta modulation. Sometimes, VoIP transcoding is done to adapt to a modern format.
Why is VoIP transcoding necessary?
The transcoding process executes in real time during the call or media exchange. Without transcoding, call quality degrades; in such cases, video streams or playback may not be permissible. Files may also lose data packets, rendering them less usable.
VoIP multi-codec transcoding optimizes technical specifications, like bitrate, resolution, aspect ratio, frame rate, sampling rate, bandwidth consumption and networking speeds. It also shrinks file sizes to fit in storage without losing quality.
How does VoIP multi-codec transcoding affect call quality and bandwidth usage?
Transcoders are software; hardware, such as a multi-transcoder integrated circuit; or a combination of ICs and an application that converts media from one format to another. Cloud-based transcoders are increasingly becoming more common in the industry. In an enterprise VoIP network, the session border controller usually governs multi-codec transcoding.
Relationship between VoIP transcoding and bandwidth
To reduce bandwidth requirements, codecs rely on data compression and decompression techniques to transmit VoIP data. Codecs offer a variety of compression rates.
Whenever data compresses for a lossy codec, the call quality decreases. Video quality also deteriorates. VoIP multi-codec transcoding with a lossy codec consumes less bandwidth. However, it improves network performance and cuts down on costs.
On the other hand, VoIP multi-codec transcoding for a lossless codec may consume loads of bandwidth. It generally relies on adaptive bitrate streaming to maintain balanced tradeoffs between call quality and bandwidth consumption during dynamic conditions.
The codec call quality depends upon bitrate, sampling rate, compression algorithm, frequency and other technical factors. If VoIP multi-codec transcoding happens to switch between wideband codecs, optimal call quality can be maintained with less bandwidth usage.
Pros of multi-codec transcoding
- Enhanced UX and customer experience. VoIP multi-codec transcoding provides stable call quality and optimized media storage.
- Dynamic operation. In situations with network congestion and limited bandwidth, a high-bitrate codec is converted into a low-bitrate codec at the target endpoint. This eliminates codec mismatch between two VoIP call endpoints in critical conditions. As a result, no call is abruptly dropped due to incompatibility.
- Reliability. VoIP multi-codec transcoding optimizes storage, and by reducing the audio or video file size, it avoids playback failure. Error correction techniques can recover any data packets lost due to multi-codec transcoding. Keep in mind: Packet loss can occur as a result of other factors beyond VoIP transcoding.
Cons of multi-codec transcoding
- Latency. VoIP multi-codec transcoding requires sufficient processing time, potentially introducing delays in the network. Lossy codecs, which are more complex, can take even more time. In situations with multiple code conversion stages, each stage causes latency and compromises the call quality, especially when parties use different codecs at their VoIP endpoints.
- Increased overhead. VoIP multi-codec transcoding can cost enterprises if one codec has to be converted into a licensed codec. Converting a low-bitrate codec to a higher one consumes memory and bandwidth. As a result, enterprises face higher costs with their VoIP networks.
Venus Kohli is an engineer turned technical content writer, having completed a degree in electronics and telecommunication at Mumbai University in 2019. Kohli writes for various tech and media companies on topics related to semiconductors, electronics, networking, programming, quantum physics and more.
