How to encode 720p, 25fps BD compliant ?

[Metal-HTPC]

hello,

when I encode 720p HD sources with 29,97 to BD compilant 720p sources I usually use changefps(59.94) in Avisynth and make a 720p59.94 x264 encode.

This time time I have a 25fps 720p HD source so I want to go for the 720p50 specification but somehow changefps(50.00) doesn't work. I get an error and don't understand why this is a wrong divisor?
There is also the possibility to not use the avisynth fps command and just go for a
720p25, which (according to http://www.x264bluray.com/home/720p-encoding) doubles the framerate with the "--pulldown double preset".
The encode works fine but plays with 50% more speed which is totally senseless.

Any advice is appreciated
thanks
regards

[junah]

Does it even have 50 original frames?

[Sharc]

What is the (avisynth) error you are getting?
--pulldown double encode with wrong playback speed: Do you watch the .264 raw stream? If so, mux it into a container (.mkv, .mp4, .m2ts) and set the framerate to 50fps

Upload a sample (few seconds duration) of your source so someone can take a look.

[jpsdr]

Originally Posted by Sharc

--pulldown double encode with wrong playback speed:

Is it a bug un x264 ? In that case, it has to be reported.

[Sharc]

Originally Posted by jpsdr

Is it a bug un x264 ? In that case, it has to be reported.

Not as I know. The OP might however have a problem with the player, hence my recommendation to mux the .264 video stream into a container for playback. Just a thought.
Btw. exactly the same topic is discussed in the videohelp forum as well …….

[FranceBB]

25p should be accepted and it shouldn't speed the video up by 50%.
Encode a few minutes like so by only using an indexer:

x264 --bitrate 25000 --preset veryslow --tune film --bluray-compat --vbv-maxrate 40000 --vbv-bufsize 30000 --level 4.1 --keyint 25 --open-gop --slices 4 --pulldown double --colorprim "bt709" --transfer "bt709" --colormatrix "bt709" --sar 1:1 --pass 1 -o "out.264" "AVS_Script.avs"

x264 --bitrate 25000 --preset veryslow --tune film --bluray-compat --vbv-maxrate 40000 --vbv-bufsize 30000 --level 4.1 --keyint 25 --open-gop --slices 4 --pulldown double --colorprim "bt709" --transfer "bt709" --colormatrix "bt709" --sar 1:1 --pass 2 -o "out.264" "AVS_Script.avs"

Otherwise, with Avisynth you can do something like:

ConvertFPS(50)
assumeTFF()
separatefields()
selectevery(4,0,3)
weave()

and then encode everything as 25i:

x264 --bitrate 25000 --preset veryslow --tune film --bluray-compat --vbv-maxrate 40000 --vbv-bufsize 30000 --level 4.1 --keyint 25 --open-gop --slices 4 --tff --colorprim "bt709" --transfer "bt709" --colormatrix "bt709" --sar 1:1 --pass 1 -o "out.264" "AVS_Script.avs"

x264 --bitrate 25000 --preset veryslow --tune film --bluray-compat --vbv-maxrate 40000 --vbv-bufsize 30000 --level 4.1 --keyint 25 --open-gop --slices 4 --tff --colorprim "bt709" --transfer "bt709" --colormatrix "bt709" --sar 1:1 --pass 2 -o "out.264" "AVS_Script.avs"


Last but not least, you can try 50p by using FFMpegSource2 as indexer and setting fpsnum 50000, fpsden 1000 like so:

FFMpegSource2("source.m2ts", fpsnum=50000, fpsden=1000, atrack=-1)

and then encode everything as 50p:

x264 --bitrate 25000 --preset veryslow --tune film --bluray-compat --vbv-maxrate 40000 --vbv-bufsize 30000 --level 4.1 --keyint 50 --open-gop --slices 4 --colorprim "bt709" --transfer "bt709" --colormatrix "bt709" --sar 1:1 --pass 1 -o "out.264" "AVS_Script.avs"

x264 --bitrate 25000 --preset veryslow --tune film --bluray-compat --vbv-maxrate 40000 --vbv-bufsize 30000 --level 4.1 --keyint 50 --open-gop --slices 4 --colorprim "bt709" --transfer "bt709" --colormatrix "bt709" --sar 1:1 --pass 2 -o "out.264" "AVS_Script.avs"

[Sharc]

Originally Posted by FranceBB

…. and then encode everything as 25i: …...

720 must be progressive for Blu-ray compliance.

[FranceBB]

Ah, right, right, only 1080i is compliant so he would have to upscale as well... possibly with Spline36 or Spline64Resize in that case... (or NNEDI + Spline).

[Metal-HTPC]

It doesn't matter if I chose "changefps(50.00)" "changefps("pal_double") or "changefps(50, 1)" it always leads to the error "error: Evaluate: System exception - Integer Divide by Zero"
The commandline I used was

--bluray-compat --level 4.1 --keyint 50 --sar 1:1 --slices 4 --vbv-bufsize 30000 --vbv-maxrate 40000 --b-pyramid none --weightp 0 --colorprim bt709 --transfer bt709 --colormatrix bt709 --merange 24

according to http://www.x264bluray.com/home/720p-encoding the blu-ray specification for 720p 25fps blu-rays has to be done using the "--pulldown double" command which makes 50 out of the 25fps. The problem is that this command doesn't work here because it doubles the playback speed. If a 720p 25fps blu ray without the framerate duplication is supported as well then I give it a try. Thanks so far guys and a good weekend

[FranceBB]

Originally Posted by Metal-HTPC

It doesn't matter if I chose "changefps(50.00)" "changefps("pal_double") or "changefps(50, 1)" it always leads to the error "error: Evaluate: System exception - Integer Divide by Zero"

Can't you just let the indexer duplicate frames to 50fps progressive?

FFMpegSource2("source.m2ts", fpsnum=50000, fpsden=1000, atrack=-1)

[huhn]

the normal none BD spec doesn't have 25p at all it is either 720p50 or 1080i50 and well yeah 1440x1080i50. which the tp well knows.

is 720 uspcale to 1080 an option for you?
if yes all you need is now set the fake-interlaced flag for x264 and you are done.

error: Evaluate: System exception - Integer Divide by Zero

can you just as a test try this:

assumeFPS(25)
changeFPS(50)

[Metal-HTPC]

Originally Posted by huhn

is 720 uspcale to 1080 an option for you?
if yes all you need is now set the fake-interlaced flag for x264 and you are done.

The stream recording hasn't the greatest quality to begin with so bloating it to a higher resolution doesn't make much sense but if I don't have any other choice..

Originally Posted by huhn

can you just as a test try this:
assumeFPS(25)
changeFPS(50)

"changeFPS(50)" also gives me the "integer devide by zero" error

shure assumeFPS(25) works but sadly 25fps isn't allowed in a 720p BD compilant encode

FFMpegSource2("source.m2ts", fpsnum=50000, fpsden=1000, atrack=-1)

I use DGAVCindex as an indexer. Didn't use FFMpeg for that before but could give it a try.

I just noticed something weird tho. The framerate of the source is specified different depending on which application I use.
DGAVCindex and MPC-HD shows it as 25fps which seems right because Belium is a PAL country and should therefore stream PAL. Tmpegenc smart renderer recognises it as 30 fps and tsmuxter as "unknown frame rate".
If this isn't 25fps then somethings very strange.

But before I continue to break my head. here is a sample for you

https://we.tl/t-ZhbKzDeUpW

thanks in advance for the help

[Metal-HTPC]

anyone?

[Stereodude]

Doubles the playback speed on what software / hardware?

[sneaker_ger]

BlankClip(fps=25)
ChangeFPS(50)

Same error?

Please run AviSynth Info Tool or avsmeter -avsinfo and avsmeter "script.avs".

https://forum.doom9.org/showthread.php?t=174797
https://forum.doom9.org/showthread.php?t=176079