It supported 8-bit, 4:2:0 encoding with 10-bit, 4:2:2 encoding on the short-term road map. The FFmpeg encoder I tested could input MXF, YUV/Y4M, MP4, and ProRes files and output transport streams (.ts) and. As you’ll see, if you don’t need to implement any non-default settings in the enhancement layer, the CBR configuration is much simpler. For live, V-Nova recommends constant bitrate (CBR) encoding, which is the default LCEVC mode. Since CRF is not the default setting, you’ll have to configure both the base and enhancement layers. There are two use cases for LCEVC-video on demand (VOD) and live-and each requires a different type of encode.īriefly, for VOD, V-Nova recommends using constant rate factor (CRF) mode, which provides a measure of per-title encoding. Then you have to configure the enhancement layer. First, you have to choose the codec for the base layer and configure that encode.
With this as background, it’s simple to understand what’s required to encode LCEVC. This backward compatibility is one of LCEVC’s greatest strengths.įigure 2. The VLC player wasn’t LCEVC-compatible when I wrote this, so it saw only the 960x540 H.264 base layer in this 1080p LCEVC encoded file. At the time I wrote this tutorial, in January 2020, the VLC player wasn’t LCEVC-compatible, so it detected and played the base layer stream, as you can see in the Codec information window on the right, and simply ignored the LCEVC data.
The enhancement layer, which provides additional detail and resolution, is encoded using the LCEVC codec.įigure 1. LCEVC compressed files have two streams: a base layer and an enhancement layer.Īs an example, Figure 2 shows the VLC player playing a 1080p LCEVC encoded file that used a 960x540 H.264 encode for the base layer. The base layer is a low-resolution encode from any existing codec, such as H.264, HEVC, VP9, or AV1, which provides backward compatibility on platforms without an LCEVC decoder. LCEVC is a hybrid codec that incorporates two layers and two technologies into each encoded stream (see Figure 1). I’ll also take a quick look at encoding speed and comparative quality. In this tutorial, I’ll detail how to encode LCEVC using FFmpeg 4.0.1-17 and the version 2.9 build 539246 of V-Nova’s P+ encoder. In fact, LCEVC has already been implemented by many streaming producers as V-Nova’s P+ codec. Of the three, LCEVC is the only one that can have an immediate impact on the streaming landscape, because it can be implemented completely in software without degrading system performance or device battery life.
Low Complexity Enhancement Video Coding (LCEVC) is one of the three MPEG codecs that will be released in 2020.
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