Question about "total-frames" setting in x265

[joelkolb]

I have just started playing with transcoding video with x265. Using MediaInfo to examine several other video files not encoded by me, in the "Encoding settings" field I will often see "total-frames=156607" or some other numeric value. Whenever I encode a video, MediaInfo always shows "total-frames=0". I don't know why this is. I'm not even sure what the total-frames setting is actually supposed to indicate. My guess would be the literal total number of frames in the video. But if that is the case, why do the videos I encode always have a value of 0? Looking at the documentation for x265, the only thing it says about total-frames is this:

If --total-frames is 1, then a stillpicture variant will be signaled, but this parameter is not always set by applications, particularly not when the CLI uses stdin streaming or when libx265 is used by third-party applications.

If I try to pass the option "--total-frames" with the number of frames in the source video, or any other number, I get the error message "unknown option -- total-frames". Can anybody help me understand the meaning of the total-frames value, why mine is always 0 when other videos have actual values, how it can be changed and whether it makes a difference? Thanks!

[Selur]

If I try to pass the option "--total-frames" with the number of frames in the source video.. unknown option -- total-frames"

So a quick look in the documentation:

--frames <integer>

The number of frames intended to be encoded. It may be left unspecified, but when it is specified rate control can make use of this information. It is also used to determine if an encode is actually a stillpicture profile encode (single frame)

https://x265.readthedocs.io/en/master/cli.html#cmdoption-frames

the total-frames reported by mediainfo is the frame count indicated by the container which is written when the container is created, if the number of frames is unknown to the application writing the container using 0 is usually the solution.


Cu Selur

[joelkolb]

Ah-ha! So I just did a quick test using the "--frames" option to pass x265 the total number of frames and now MediaInfo does indeed show a value for "total-frames". @Selur Thank you for that information!