Convert H265 to H264 losslessly

[thecrock]

Hi there,
I have a bunch of hd files that i need to convert from H265 to H264, I need to convert losslessly. Can any member here advise on how to do this.

Peace

[pandy]

Generally this is not possible - perhaps it could be done without converting video from transformation domain to raw video but AFAIK there is no ready to use product (and even it such product ever exist then it will be rather expensive - not for home user).

[VoodooFX]

I have a bunch of hd files that i need to convert from H265 to H264, I need to convert losslessly. Can any member here advise on how to do this.

Use lossless option, "-q0".

[thecrock]

Thanks for the help guys.
I read that VLC could do this but i try and i get a loop saying the file already exists.

What does this mean?

Use lossless option, "-q0".

[VoodooFX]

It's option to use with x264.exe.

Or you can use ffmpeg:
ffmpeg -i input265.mkv -c:v libx264 -preset medium-crf 0 -c:a copy output264.mkv

[pandy]

Lossless encoding (mentioned "-q0") will not provide lossless conversion (transcoding) also if your source is normally encoded (i.e. average video) using "-q0" will elevate bitrate without any quality gain over source.

[ProWo]

Use

ffmpeg -i input265.mkv -c:v libx264 -preset medium -crf 18 -c:a copy output264.mkv

This gives you a video that shows no loss of quality visually and produces a file size that is still acceptable.
There is no lossless re-encoding of an already compressed video (x265).

[Santiago]

I have used HandBrake and Shutter Encoder. I have not noticed any loss of quality. These two programs are free.

[VoodooFX]

Of course it will be lossless, your video will be bit to bit same after conversion, unless it's not 8 bits.

Lossless encoding (mentioned "-q0") will not provide lossless conversion (transcoding)

There is no lossless re-encoding of an already compressed video (x265).

[pandy]

Of course it will be lossless, your video will be bit to bit same after conversion, unless it's not 8 bits.

Lossless encoding (mentioned "-q0") will not provide lossless conversion (transcoding)

Nope but feel free to try and prove it - i will be happy to be wrong - you can use video compare feature (or subtract video from source and calculate delta) or even some dedicated video measurement like SSIM or generic PSNR. There is many ways to prove that there is no possible to losslessly transcode video from one lossy codec to another...
Good luck.

[VoodooFX]

Please stop spreading nonsense.

[pandy]

Please stop spreading nonsense.

Agree - please stop spreading nonsense.

[thecrock]

Thanks for all the interest guys.
This is where i am.


I have inherited a project file of an edit which is not quite finished. It is a DaVinci project.

The project was originally on a pc but moved to an external SSD.
I have relinked all of the files except a number of video files that were shot on a different camera. When i bring these into the media pool i only get audio.
The videographer suggested converting the files to H264 which i tested using VLC media player. Now when i add the video to the project i only get the video no audio.

I tried the files in Premiere pro. The H265 original only plays audio in Premiere Pro. After converting to H264 in VLC the file plays perfectly in Premiere Pro.
In VLC i used the option to convert to H264 MP3 in MP4.

So DaVinci plays only the the audio of the H265 and video only of the H264.

Anyone have any idea what could be going on?

[pandy]

IMHO export project as for example Prores+audio PCM and later convert it to H.265 and/or H.264 with audio codec you wish.

[thecrock]

Hi,
thanks for the advice.
I'm hoping its something wrong with DaVinci, as the files play fine in PremierePro after converting from H250 to H264 with VLC.

[pandy]

Hi,
thanks for the advice.
I'm hoping its something wrong with DaVinci, as the files play fine in PremierePro after converting from H250 to H264 with VLC.

Perhaps, that's why i suggested to export your project in something like intermediate codec and rely on final encoding with working tool (i mean not so many people use DaVinci so you may face issue trying to solve some DaVinci misbehavior).
Sometimes it is easier to give up instead trying to solve tool hiccup.

[jagabo]

Of course it will be lossless, your video will be bit to bit same after conversion, unless it's not 8 bits.

Lossless encoding (mentioned "-q0") will not provide lossless conversion (transcoding)

Nope but feel free to try and prove it - i will be happy to be wrong

-qp 0 is a special lossless mode in x264. Many h.264 decoders can't decompress this so it may not be much use to the OP.

https://trac.ffmpeg.org/wiki/Encode/H.264#LosslessH.264

See the attached samples.

265.mkv is a short x265 encoded video
264.mkv is 265.mkv encoded with ffmpeg libx264 at -qp 0
_265_to_264 is the ffmpeg batch file used to do that encoding
_PSNR.BAT runs ffmpeg to compare 264.mkv to 265.mkv, shows PSNR = inf
_SSIM.BAT runts ffmpeg to compare 264.mkv to 265.mkv, show SSIM = 1.000000
diff.avs subtracts 264.mkv from 265.mkv to show there are no differences

[lollo]

Master VoodooFX docet

[pandy]

Of course it will be lossless, your video will be bit to bit same after conversion, unless it's not 8 bits.

Lossless encoding (mentioned "-q0") will not provide lossless conversion (transcoding)

Nope but feel free to try and prove it - i will be happy to be wrong

-qp 0 is a special lossless mode in x264. Many h.264 decoders can't decompress this so it may not be much use to the OP.

https://trac.ffmpeg.org/wiki/Encode/H.264#LosslessH.264

See the attached samples.

265.mkv is a short x265 encoded video
264.mkv is 265.mkv encoded with ffmpeg libx264 at -qp 0
_265_to_264 is the ffmpeg batch file used to do that encoding
_PSNR.BAT runs ffmpeg to compare 264.mkv to 265.mkv, shows PSNR = inf
_SSIM.BAT runts ffmpeg to compare 264.mkv to 265.mkv, show SSIM = 1.000000
diff.avs subtracts 264.mkv from 265.mkv to show there are no differences

I'm not arguing with x264 lossless mode - h.265 decoding is not bit exact unless h.265 was not encoded losslessly.
Using lossless h.264 to encode lossy coded h.265 is pointless.

[lollo]

Using lossless h.264 to encode lossy coded h.265 is pointless.

Sure, but I think VoodooFX introduced his (right) assumption since the beginning just as provocation

[VoodooFX]

The guy clearly is missing few bolts, just leave him alone with his nonsense posts.

[pandy]

Using lossless h.264 to encode lossy coded h.265 is pointless.

Sure, but I think VoodooFX introduced his (right) assumption since the beginning just as provocation

Well... i didn't assumed that OP is not serious when he ask on transcoding losslessly from h.265 to h.264.