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

[Stereodude]

Doubles the playback speed on what software / hardware?

[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?

[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

[Sharc]

No problem here.
Changefps(50) duplicates the frames, as expected.

Perhaps reinstall your Avisynth.

[FranceBB]

Originally Posted by Sharc

No problem here.
Changefps(50) duplicates the frames, as expected.

Yep, I just checked as well and it works absolutely fine.


@Metal-HTPC... your source is a normal HD file in H.264 yv12 (4:2:0 planar) 8bit at 25fps CFR which has been already encoded by someone at a very low bitrate, therefore there are some pretty bad blocking artifacts as it's starved, like:

#indexing
video=FFVideoSource("Candlemass - Graspop 2019.264")
audio=FFAudioSource("Candlemass - Graspop 2019.aac")
AudioDub(video, audio)

#Clipping
Limiter(min_luma=16, max_luma=235, min_chroma=16, max_chroma=240)

#Blending
ConvertFPS(50)

#Loudness Correction
ResampleAudio(48000)
Normalize(0.22)

Either duplicating frames with ChangeFPS(50) or blending with ConvertFPS(50) works absolutely fine. Link

I won't send you back the encoded sample as it's 50 minutes long and the file would be too big to upload with a BD-Tier bitrate.
For the records, whoever squeezed almost 1h of video in 500 MB, did a poor job: it's a concert and there are many dark scenes with strong lights which had to be encoded with attention; instead, someone just used random settings which made it look pretty bad, without details and even with blocking artifacts. Encoding it in BD with 25Mbit/s bitrate for BD compatibility is like giving a castle to a homeless person... well... you know what I mean.
Anyway, I hope it helps.

Cheers,
Frank.

[Metal-HTPC]

Originally Posted by 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

I willl try those out to see what is wrong in my setup, thanks for the suggestion.

Originally Posted by Sharc

....................
Perhaps reinstall your Avisynth.

will do so but have to check what the above mentioned tools have to say.

Originally Posted by FranceBB

...............
I won't send you back the encoded sample as it's 50 minutes long and the file would be too big to upload with a BD-Tier bitrate.
For the records, whoever squeezed almost 1h of video in 500 MB, did a poor job: it's a concert and there are many dark scenes with strong lights which had to be encoded with attention; instead, someone just used random settings which made it look pretty bad, without details and even with blocking artifacts. Encoding it in BD with 25Mbit/s bitrate for BD compatibility is like giving a castle to a homeless person... well... you know what I mean.
Anyway, I hope it helps.

No problem at all.
I know the quality is bad but this is the way they streamed it. I think they had to do it in order to make shure that the broadcast plays flawless. Those belgium festival streams never improved much over the years but they are still a better souvenir than nothing.
Regarding making a BD out of it you are pretty much right. I should go for a x264 SD 720x576 resolution here and the show easily fits on a dvd-r or even a cd-r..
Thanks for the help, guys. I'm away for a few days and try to get the problems fixed when I return. It shure looks like it's a problem with my setup.

[Metal-HTPC]

works fine now.

The problem was that I still used DGindex and DGAVCindex which are outdated for years and seem to have problems with todays (weird) streams.

I switched to FFVideo and now everything works fine.

Thanks for the support guys !
cheers

[videoh]

DGAVCIndex is deprecated for years. DGIndex is intended for MPEG2 video in ES/VOB/Transport, where it continues to work very well.

Not sure what you mean by "today's (weird) streams" but if it is AVC/HEVC/MPEG/VC1 in ES/Transport/Program Stream/MKV/MP4, and possibly with HDR, then DGDecNV is just for you!