11/10/2023 0 Comments Ffmpeg crf cqp same![]() ![]() This will cause the bit rate allocation to vary over time.įor example, the following figure shows two different videos (BBB big buck bunny and TOS tears of steal), encoded with different levels (17 and 23), using constant quantization parameter CQP and constant quality CRF mode respectively When setting CRF=18, the QP will be set higher for scenes with relatively large motion, and the QP will be lowered for frames with relatively low motion. Of course, there will be some slight fluctuations depending on the type of frame, so ignore it. In encoding, if Qp=18, then each frame is QP=18. He did this by taking sports into account. In order to make the subjective quality feel similar, different QP will be used. CRF will compress each frame with a different size. ![]() However, the CRF mentioned here is a bit more complicated than the constant quantization parameter. Usually this will cause the bit rate of the entire video sequence to be unstable. ![]() This quantization parameter QP defines how much information is lost from a pixel macroblock. In technical terms, the same quantization parameter QP is used. Generally, in order to obtain a constant quality encoding, we can compress every frame of the same type with the same size, that is, throw away the relatively same amount of information. For other usage scenarios, please use other rate control modes.ĬRF is a constant quality coding method, which is the opposite of constant bit rate (CBR). You should use crf encoding in offline file storage to obtain an optimal encoding method. Approximately a difference in the value of crf of 6 will cause the file size to double or halve. If you are not sure which crf value to use, please use the default value first, and then adjust it according to your subjective impression of the output quality. In ffmpeg, crf is used like thisįfmpeg -i input.mp4 -c:v libx264 -crf 23 output.mp4įfmpeg -i input.mp4 -c:v libx265 -crf 28 output.mp4 On x264, the general value is 18-28, and the default value is 23. The lower the value, the better the quality and the larger the file size. text-ĬRF is the default quality/rate control setting in 264 and 265. This article is translated from, if it is inappropriate, please advise. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |