Level 4.1 reference frames free
Jul 22, 2014 At 1920x1080, 4 reference frames is the max to stay within Level 4. 1. Period. As said, you can specify both level 4. 1 and 5 reference frames on the settings. You essentially tell x264 to jot down level 4. 1 on bitstream despite being not 4. 1 compliant. That does not mean the encoded file is level 4. 1 compliant, it is NOT.
Increasing the number of reference frames also dramatically increases the encoding time, since motionestimation search, which is the slowest part of video encoding, has to occur on all possible reference frames in order to find the best match.
When encoding to x264, the user can supply the x264 level information in two ways: level 41 (Without dot)level 4. 1 (Using a dot between the numbers) In both cases, the encoded video shows the level as 4. 1, but only in the second case the reference frames are correctly computed. How to reproduce:
Online calculator. H264 Maximum References Frames. H264 Maximum References Frames. H264 Maximum References Frames
XAVC is a recording format designed by Sony that uses level 5. 2 of H. 264MPEG4 AVC, which is the highest level supported by that video standard. XAVC can support 4K resolution (4096 2160 and 3840 2160) at up to 60 frames per second (fps).
More reference frames result in slightly higher compression quality, but increased decoding complexity. In practice, going above 5 rarely has much benefit. Determined partly by speed as well as videocodecprofile.
While the best frame for this purpose is usually the previous frame, the extra reference frames can improve compression efficiency andor video quality. Note that different reference frames can be chosen for different macroblocks in the same frame. The maximum number of concurrent reference frames supported by H. 264 is 16.
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