Staxrip VBR hevc

[Delibit]

Ive been trying to understand staxrip parameters of hevc codec to compres my video to the max without loosing quality on my videos.

Variable bitrate hevc 200-600kb range.
But I dont understand Vbv buffsize and Vbv .

I have an intel gpu but i also read programs for nvidia and amd to bench there Vbv settings but none for intel.

My goals is max compression but fluid playback and then after potential battery drainage make a final hevc parameter set for my mobile device.

My atemp gave me a video of thousand kb bitrates that are huge compared to the source file.

My device is an lenovo miix 830 with only 1024x768 resolution with avc hardware accelaration only but hevc plays well.

[LigH.de]

VBV (Video Buffer Verifier) is a technique to ensure that the encoder will produce a video stream a specific decoder with only a limited decoding buffer or limited reading speed can still decode (e.g. a consumer player reading from slower media like optical disks, or playing video over a network with a limited bandwidth).

If you play videos locally on a PC from the harddisk with software decoders, VBV limits are probably so high that you don't need to care about them. Hardware accelerated decoders on a GPU may have some limits too, but also probably a lot higher than mobile or set-top consumer players reading from disks, network, or Flash memory. Certainly a lot higher than 600 kbps.

Compressing to HEVC "without losing quality" will probably require a lot more than 200-600 kbps (except your video dimensions are as small as a poststamp). Lossless compression will take as much space as it needs to be lossless and don't care about any bitrate options; you will probably not want that. Of course it will be a lot bigger than your previously compressed video, which already lost a lot of quality compared to some uncompressed original size.

If you compress from the same 100% original huge video source which is not yet compressed with a lossy algorithm, HEVC can probably achieve a better quality than many other algorithms with the same target size. But if you compress a video already compressed with a lossy algorithm further again, trying to get a lesser bitrate, you will certainly lose more quality, because HEVC will waste some quality on the video artifacts already present on your so-called "original" video which already lost quality before.

[Delibit]

The videos are 720p webvideos.
They arnt all to high def but respectively comfortable.
Some come at a 1000kb and some to say 1800 kb.

Personally i dont need +1200 avc videos quality.
I would like to save the quality of avc video@1000-1200kb at minimum filesize.

Variable bitrate is what I need I think but I cant set min-max bitrate.


There is also the fact that my gpu supports hardware avc coding vs software coding hevc.
takes longer to encode thne the video is long but playback doesnt use 5% more resource then my minimum 1200kb avc videos. Suppose the decoding benefites from the avc hardware still.

[LigH.de]

The x265 encoder supports 2-pass VBR with a target average bitrate and a VBV maximum bitrate (but also requires a VBV buffer size in this case).

If you compress AVC video further to HEVC video with an even lower bitrate, you will lose quality for sure. Whether you will recognize the loss or not, is a different topic...

There is no benefit from AVC decoding hardware for HEVC video. The algorithms differ too much. If your decoder chip does not support HEVC decoding, it won't be used at all.

[Delibit]

I have nothing to base Vbv buffsize on.

[LigH.de]

If your main playback device is a PC with a lot of RAM, just calculate your target bitrate multiplied with a convenient buffering time (e.g. 5 to 10 seconds; the default maximum GOP size is also often targeted at 10 seconds if not limited for compatibility with a specific device or specification).

In your case, a simple suggestion: 1200 kbit/s * 10 s = 12000 kbit