Local bitrate limiting?

[Comatose]

--vbv-maxrate <integer> Max local bitrate (kbit/s) [0]
How strict is this? I set it to 2450 and the peak bitrate was 2987.
Am I doing something wrong?

Here's the rest of my commandline:
x264 --pass 2 --bitrate 2000 --stats ".stats" --ref 3 --mixed-refs --no-fast-pskip --no-cabac --psy-rd 0:0 --partitions p8x8,b8x8,i4x4 --vbv-bufsize 2000 --vbv-maxrate 2450 --me umh --threads auto --thread-input --progress --no-psnr --no-ssim --output wee.mp4 "wee.avs" --sar 64:45 --colormatrix bt709

720x576 24p video, encoding for the third gen Zune.

[Dark Shikari]

How strict is this? I set it to 2450 and the peak bitrate was 2987.
Am I doing something wrong?How are you measuring the "peak bitrate"?

You have to measure the bitrate with regards to the same buffer size as you've used in the encoder.

Also note that x264 is guaranteed to print a warning if the limit is violated.

[Comatose]

I don't see any warning.

I played the entire file with DGAVCIndex then looked at the value under Bitrate (Max).
How can I measure it differently to be sure the same buffer size is being used? (I trust x264's having not printed a warning, but I'm curious :p)

[Sergey A. Sablin]

measuring bitrate in existent stream has nothing to do with buffer size, however real maximum bitrate in the compliant stream might be up to vbv_max_rate + buffer_size * 1 sec.

you might be confused by this:
--vbv-maxrate <integer> Max local bitrate (kbit/s) [0]
it is not maximum bitstream bitrate, but maximum rate to be supported by the channel, to transmit stream correctly.

[Manao]

vbv_max_rate + buffer_size * 1 sec.That is, if you define bitrate as the size in bits over a period of 1 second. Over a period of time T, the maximum reachable bitrate is (vbv_max_rate * T + buffer_size) / T, which simplifies into vbv_max_rate + buffer_size / T.

[Comatose]

Ah, I see. Thanks! :)