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No speed up after upgrading GPU

Started by the_michael, October 16, 2022, 08:50:47 PM

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the_michael

Recently I've moved from GTX 1060 to RTX 3060TI and expected shorter time of encoding my mkv files into mp4. But there is no speed up at all. What I do exactly is encoding .mkv files recorded with OBS software into .mp4 using Video output : Nvidia H264 with RC mode set to Constant Quality

At my last upgrade from 750TI to 1060TI speed up was noticeable but now there is no difference.  Any idea why is that? Windows says that GPU drivers are up to date.

Moreover the best encoding time (10-12 minutes for about 90min .mkv) was achievable in Avidemux 2.76 with RC mode set to "Constant Quality". In 2.81 there is no such RC Mode. When I choose "Constant Quantizer" it takes at least 40 minutes if I select "Fast" Preset. What am I doing wrong?

szlldm

The RTX 3060TI has 6th (Turing) generation NVENC, while the GTX 1060 has 4th gen (Pascal).
(OT: 5th gen Volta has similar performance as Pascal's NVENC)
Turing had improved mainly on quality, not on performance.
Table 3. in NVENC_Application_Note.pdf shows that at higher preset (eg. P7) the newer NVENC is even slower than the 4th gen; certainly the end result has better quality.

Blues

Quote from: the_michael on October 16, 2022, 08:50:47 PMRecently I've moved from GTX 1060 to RTX 3060TI and expected shorter time of encoding my mkv files into mp4. But there is no speed up at all. What I do exactly is encoding .mkv files recorded with OBS software into .mp4 using Video output : Nvidia H264 with RC mode set to Constant Quality
Sorry, but something is off here. MP4 and MKV are containers. While H.264 is a codec. You can have H.264 video in MKV container or in MP4 container. There is absolutely no need to re-encode, only re-mux is needed. Unless there is some other reason for re-encoding ...

the_michael

@szlldm. Thanks! That explains a lot.

@Blues I use OBS which says that MKV is more safe in case of BSOD or any other reason of unexpected break of recording. I record in high quality then reencode it in order to reduce the file size. I wasn't able to set parameters in OBS which produce small file size with good quality.  I've read on some forum that custom muxer settings may be very useful. I guess I need to get know more about fundamentals about encoding.

eumagga0x2a

Quote from: the_michael on October 18, 2022, 12:04:21 PMI use OBS which says that MKV is more safe in case of BSOD or any other reason of unexpected break of recording.

There are methods to create live-streaming-compatible MKV and live-streaming-compatible (fragmented) MP4 files. Usual MKV and MP4 containers are neither suitable for streaming nor designed to survive a catastrophic event like a system crash or power loss. They are equally bad at that.

The only format which is natively designed for streaming and is robust enough to preserve integrity of already recorded data is MPEG-TS.

If OBS records video in YUV444 format (full chroma resolution), this may be desirable from the point of view of preserving a high-quality master. Re-encoding it later in YUV420 (1/4 of chroma resolution) would make it widely compatible with hardware accelerated video decoders (and optionally enforce constant frame rate), so there may be valid reasons to go this way.

the_michael

@eumagga0x2a Thanks. I just discovered what YUV is  :-[  I've checked my OSB settings and it turned out I recorded all my videos in NV12 format whatever is this. I need to experiment with different color spaces now as I can see there are few interesting options there. Fortunately there are lot of great education videos on YT about it.

eumagga0x2a

NV12 = one plane (read it as a location in memory where a data array starts) with luminance in full resolution, a second plane with interleaved U and V chrominance values at 1/4 resolution ((width/2)*(height/2)) each, cmp. https://stackoverflow.com/questions/17487048/nv12-format-and-uv-plane