What's the maximum compression ratio for h264 and h265 encoding now?

[yu__luo]

Well, in my situation, my encoding configuration is:

resolution=3840x2160

target bitrate=500kbps

fps=30

codec=h264

RC mode=CBR

And the real encoded bitrate is 4000kbps. And I found some sentences in this forum that said the limit of the compression ratio is 500x.

I can understand the real bitrate is mismatched now. But I want to make sure that the limit of the compression ratio is still 500x? Is h265 encoding the same?

BTW, there is a parameter named BitrateLimit in CodingOptionValue. I tried to set it to false, and nothing changed.

[Dmitry_E_Intel · Accepted solution]

For AVC case, min bitrate logic is here: https://github.com/Intel-Media-SDK/MediaSDK/blob/master/_studio/mfx_lib/shared/src/mfx_h264_enc_common_hw.cpp#L3504

Are you sure you turned off BitrateLimit? I mean did you set BitrateLimit=MFX_CODINGOPTION_OFF (not "=false")?

As for HEVC, I don't think MediaSDK has similar limit logic.

BTW, you always can get internal (actual) MSDK parameters by GetVideoParam function and check if MSDK made any tuning to initialization parameters.