![]() ![]() Some browsers may choose to allow other codecs as well.īelow are the video codecs which are required in any fully WebRTC-compliant browser, as well as the profiles which are required and the browsers which actually meet the requirement. WebRTC establishes a baseline set of codecs which all compliant browsers are required to support. ![]() Beyond this simple maximum resolution request, specific codecs may offer further ways to ask for specific media configurations. The sender is not required to support this mechanism, however, so you have to be prepared to receive media at a different resolution than you requested. This is done by sending an a=imageattr SDP attribute to indicate the maximum resolution that is acceptable. SDP supports a codec-independent way to specify preferred video resolutions ( RFC 6236. It's encouraged that video be encoded at a frame rate and size no lower than that, since that's essentially the lower bound of what WebRTC generally is expected to handle. Unless the SDP specifically signals otherwise, the web browser receiving a WebRTC video stream must be able to handle video at 20 FPS at a minimum resolution of 320 pixels wide by 240 pixels tall. General codec requirementsīefore looking at codec-specific capabilities and requirements, there are a few overall requirements that must be met by any codec configuration used with WebRTC. Of secondary importance is the need to keep the video and audio synchronized, so that the movements and any ancillary information (such as slides or a projection) are presented at the same time as the audio that corresponds. While compression is always a necessity when dealing with media on the web, it's of additional importance when videoconferencing in order to ensure that the participants are able to communicate without lag or interruptions. This guide reviews the codecs that browsers are required to implement as well as other codecs that some or all browsers support for WebRTC. These two RFCs also lay out options that must be supported for each codec, as well as specific user comfort features such as echo cancellation. However, RFC 7742 specifies that all WebRTC-compatible browsers must support VP8 and H.264's Constrained Baseline profile for video, and RFC 7874 specifies that browsers must support at least the Opus codec as well as G.711's PCMA and PCMU formats. Which codecs can be within those tracks is not mandated by the WebRTC specification. WebRTC uses bare MediaStreamTrack objects for each track being shared from one peer to another, without a container or even a MediaStream associated with the tracks. ![]()
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