Slow Nvidia/Intel transcode

[oxydius]

Server Version#: 1.19.3.2740
Player Version#: 4.32.2

My Linux server uses its Nvidia Quadro P400 for H.265 decoding and weak Intel J1900 CPU with QuickSync for HW H.264 encoding.

With 4K source content it’s too slow to download the raw images from the Nvidia GPU and encode them on the Intel GPU. Playback is less than 1x so it keeps pausing to buffer.

Is there a Plex setting to force transcode sessions to use the same device? For example, forcing Nvidia decode->encode or fallback to Intel decode->encode?

Here’s the relevant part of the Plex Transcoding log :

<Variant id="a6465c20-9f23-4845-836d-9b3a90e4f957" targetBitrate="18283" context="streaming" sourceVideoCodec="hevc" sourceAudioCodec="aac" videoDecision="transcode" audioDecision="transcode" protocol="dash" container="mp4" videoCodec="h264" audioCodec="aac" audioChannels="2" transcodeHwRequested="1" transcodeHwDecoding="nvdec" transcodeHwEncoding="vaapi" transcodeHwDecodingTitle="NVIDIA (NVDEC)" transcodeHwEncodingTitle="Intel (VA API)" transcodeHwFullPipeline="0">
<Media audioProfile="lc" id="6247" videoProfile="main 10" audioChannels="2" audioCodec="aac" bitrate="17412" container="mp4" duration="7139508" height="1280" optimizedForStreaming="1" protocol="dash" videoCodec="h264" videoFrameRate="24p" videoResolution="1080p" width="3062" selected="1">
<Part audioProfile="lc" deepAnalysisVersion="4" id="6248" indexes="sd" requiredBandwidths="26075,22210,16252,14636,13345,12076,8510,8394" videoProfile="main 10" bitrate="17412" container="mp4" duration="7139508" height="1280" optimizedForStreaming="1" protocol="dash" width="3062" decision="transcode" selected="1">
<Stream bitrate="17156" codec="h264" codedHeight="1608" codedWidth="3840" default="1" displayTitle="4K (HEVC Main 10)" frameRate="23.975999999999999" height="1280" id="13187" requiredBandwidths="25537,21675,15737,14121,12829,11561,7933,7847" streamType="1" width="3062" decision="transcode" location="segments-video" />
<Stream bitrate="256" bitrateMode="cbr" channels="2" codec="aac" default="1" displayTitle="Unknown (AAC 7.1)" id="13188" requiredBandwidths="512,512,512,512,512,512,512,512" selected="1" streamType="2" decision="transcode" location="segments-audio" />
</Part>
</Media>
</Variant>

[ChuckPa]

When the Nvidia drivers are installed, you’ll see both the QSV and Nvidia device entries in /dev/dri.

The QSV entry is usually renderD128
The next device (Nvidia) is renderD129

To specify it, add HardwareDevicePath="/dev/dri/renderD129" to Preferences.xml

[oxydius]

Thanks a lot, exactly what I was looking for.