![]() ![]() It does this by taking motion into account. It will compress different frames by different amounts, thus varying the QP as necessary to maintain a certain level of perceived quality. This typically leads to a hugely varying bitrate over the entire sequence.Ĭonstant Rate Factor is a little more sophisticated than that. … The quantization parameter defines how much information to discard from a given block of pixels (a Macroblock). Werner Robitza explaining why CRF still allows to save bits in comparison to setting constant QP: It worth noting that this is still different from CRF because constant quality, as it is determined by -cq, sets constant quantization parameter (CQP) instead. You probably want to consider that to help in your case. ![]() Dennis Mungai's detailed answer to ' How can I use CRF encoding with nvenc in ffmpeg?' at Superuser suggests to use -cq:v 19 and -rc:v vbr parameters instead to get constant quality with variable bitrate. with ffmpeg -h encoder=hevc_nvenc -hide_banner. You can check what the encoder supports, e.g. ![]() Needless to say, it always massively outperformed h264_nvenc in terms of quality for a given bitrate, while also being slightly faster.The hardware accelerated encoders do not support Constant Rate Factor (CRF, -crf) to determine size/quality ratio. Using the 'slow' preset, av1_nvenc outperformed hevc_nvenc in terms of encoding speed by 75% to 100% while performing above tests. It produces fewer artifacts and the ones it does produce are less jarring to my perception.Īt higher bitrates I had a hard time finding differences between the two encoders in terms of subjective visual quality. In terms of quality at low bitrate cbr settings, it seems to outperform it even. The encoder seems to be trading blows with hevc_nvenc. Timo Rothenpieler merged the NVENC AV1 encoding support and summed it up as: This weekend, FFmpeg added support for using NVENC AV1 with the new NVIDIA GeForce RTX 40 series cards. With the Intel Arc Graphics, AMD Radeon RX 7000 series, and NVIDIA GeForce RTX 40 series, GPU-accelerated AV1 encoding is now widely available for this royalty-free video codec that is becoming more and more popular. ![]()
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