question on JM encoding speed

[stoneiii]

I'm using a JM encoder with version 17.2.
When it encodes a sequence with the resolution 800*600, color format yuv420, it can only encodes 3 or 4 frames per hour! :mad: Other parameterw are set as default. (High profile,CABAC enbled. )The search algorithm is fast full research. I had changed the search algorithm into simplified Hexagonal search, but the speed didn't rise.
Is this phenomenon normal? How can I adjust the encoding parameter to raise the speed?

Thank you.

[kieranrk]

This is normal. JM is a slow encoder.

[Dark Shikari]

This is the difference between toy encoders and real software.

[stoneiii]

I have been using x264 for a period of time. Recently, we want to try the expanded color space such yuv422, rgb in FREXT profiles. These color spaces are not supported by x264. That's why we try JM. I have understood JM is very slow. But encoding at the speed of less than 10 frames per hour is too slow to even make an experiment! How long shall I spend encoding a sequence with several hundred frames! OMG.......

BTW, is there any existing decoder capable of decoding yuv422,yuv444 or rgb? I find the definition of high444 profile in ffmpeg, but its color spaces are not fully supported.

Thank you.

[LoRd_MuldeR]

I have been using x264 for a period of time. Recently, we want to try the expanded color space such yuv422, rgb in FREXT profiles. These color spaces are not supported by x264. That's why we try JM. I have understood JM is very slow. But encoding at the speed of less than 10 frames per hour is too slow to even make an experiment! How long shall I spend encoding a sequence with several hundred frames! OMG.......

As was mentioned before, the JM reference encoder was never intended to be used for any real production.
It's more a "proof of concept" and serves as a reference for encoder developers. It's not intended to be used by end-users!

BTW, is there any existing decoder capable of decoding yuv422,yuv444 or rgb? I find the definition of high444 profile in ffmpeg, but its color spaces are not fully supported.

AFAIK adding support for more color spaces to x264 is one of this year's GSoC (http://wiki.videolan.org/SoC_x264_2011#4:4:4_and_4:2:2_colorspaces) projects, so just be patient...

[kieranrk]

AFAIK adding support for more color spaces to x264 is one of this year's GSoC (http://wiki.videolan.org/SoC_x264_2011#4:4:4_and_4:2:2_colorspaces) projects, so just be patient...

The person who was going to do that task was not available over the summer.

[Blue_MiSfit]

Mainconcept has an H.264 DirectShow decoder that can do 4:2:2 10 bit.

It's called the H.264 / AVC Broadcast Decoder: http://www.mainconcept.com/products/apps-plug-ins/decoding/decoder-packs/h264avc-broadcast.html

This is the only capable software decoder I know of, and it costs $230. It's good though, Mainconcept makes some of the best "pro" stuff out there.

Derek

[kieranrk]

Mainconcept has an H.264 DirectShow decoder that can do 4:2:2 10 bit.


The divx decoder can also decode 422 (not sure about 10-bit)

[jakor]

divx and mainconcept are pretty one company.