x264 encode not seekable

[mariner]

Greetings. Appreciate any kind assistance with making x264 encode seekable.

Using the following script, but output not seekable in Avidemux.

Many thanks and best regards.


x264 --fps 25 --crf 20 --tune film --bluray-compat --vbv-maxrate 40000 --vbv-bufsize 30000 --level 4.1 --keyint 25 --open-gop --slices 4 --colorprim "bt709" --transfer "bt709" --colormatrix "bt709" --sar 1:1 -o output.mkv input.avs


input.avs
DSS2("in.ts", preroll=50, lavs="L3", lavd="L3",fps=25000, fps_den=1000,tc_offset=-1)

[nevcairiel]

AFAIK, x264 mkv files do not have an index, you could remux it with mkvmerge, for example, to generate an index, which makes the files seekable, or output to another format, like mp4.

[mariner]

Thanks for the kind reply, nevcairiel.

Remuxing with mkvmerge did not work, neither did output to .264 and mux into mkv.

[kuchikirukia]

Avidemux support open GOP?

[hello_hello]

Some media players will create their own index when you open an MKV without one. MPC-HC for example. That means you can open an MKV with MPC-HC while the video is still being encoded and it'll be able to seek.
Otherwise as nevcairiel suggested, remuxing with MKVMerge should make it seekable. If it's not when opening it with AviDemux, I'm not sure why. Maybe try a test encode without any of the Bluray compatibility options and if that's seekable, you should be able to find the culprit through a bit of trial and error.

PS. I was under the impression for Bluray compatibility the output must be .264, not MKV.
http://forum.doom9.org/showthread.php?t=154533
http://www.x264bluray.com/home/1080i-p

I can't remember the exact reason, but is that no longer the case, or does it tend not to matter?

[mariner]

Was anyone able to get x264 encode to seek in AviDemux? Appreciate if you could kindly share the script used.
Many thanks and best regards.

[kuchikirukia]

Of course h264 seeks in Avidemux. Jesus Christ, all you had to do was load one to see.

[hello_hello]

It seeks fine for me after remuxing. Default x264 settings with the slow speed preset.

[mariner]

It seeks fine for me after remuxing. Default x264 settings with the slow speed preset.

Thanks hello.

The culprit would appear to be --bluray-compat. Does anyone know why?

[Asmodian]

I believe it is because it sets OpenGOP.

[sneaker_ger]

--bluray-compat does not imply --open-gop.

[hello_hello]

It's a complete mystery to me, but I played around a little, testing various combinations and it seems....

This command line results in an output that AviDemux can't seek.

--level 4.1 --bluray-compat --open-gop --slices 4 --vbv-bufsize 30000 --vbv-maxrate 40000

It can seek when using this command line:

--level 4.1 --bluray-compat --open-gop --slices 4

This seems to be the problem "no seeking" combination. --nal-hrd vbr being something that's included in --bluray-compat

--nal-hrd vbr --open-gop --vbv-bufsize 30000 --vbv-maxrate 40000

The VBV settings with just --nal-hrd vbr are fine, and with just --open-gop it's fine, but put the three together and AviDemux won't seek. I've no idea why. I was testing by re-encoding a standard definition AVI I had handy.

[sneaker_ger]

Without vbv parameters HRD is not used at all. So "--nal-hrd vbr --open-gop" is equal to "--open-gop" when not accompanied by vbv settings. That explains why all three are required, i.e. it's the only combination with OpenGOP and HRD.