Quote:
Originally Posted by LigH
If the encoder implements VBV checks correctly, then you can trust the result being decodable in a device with given limits.
From my experience in a DVD authoring studio, peaks are not your worst concern. I remember DVD Video material with occasional 13 Mbps GOP peaks causing no issues, but a permanent 10 Mbps burst being rejected by the authoring tool. The development of the bitrate during several seconds is the criterion, not a single GOP peak.
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And one nice feature of x265 is that, if not otherwise specified, it will pick the lowest level that accommodates the frame size and fps, and then set vbv-maxrate and vbv-bufsize to the maximum values for that level. So it's pretty hard to make a non-complaint stream, unlike x264 which requires VBV parameters to be set manually (fixed in some patches).
For DVD, and all VBV cases, remember that a "peak" is measured over a number of bytes, so even if a single GOP is at more than 13 Mbps, the peak as defined by VBV can still be <10 Mbps. DVD GOPs are around half a second. average bitrate per GOP and peak bitrate converge a lot more with longer GOPs, but you can still have things that look non-compliant but aren't. And sometimes something that looks compliant that isn't, like if two clips are concatenated with the first ending in a peak and the second starting with a peak. Both could have been compliant by themselves, but VBV gets violated at the stich point.