# Why no B-Frames for NVENC

**URL:** <https://community.wowza.com/t/why-no-b-frames-for-nvenc/40875>\
**Category:** Wowza Streaming Engine\
**Created:** [January 2, 2014, 4:58pm UTC](https://community.wowza.com/t/why-no-b-frames-for-nvenc/40875 "2014-01-02T16:58:52Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![Jason\_Ritzke](https://avatars.discourse-cdn.com/v4/letter/j/ecc23a/32.png) [@Jason\_Ritzke](https://community.wowza.com/u/Jason_Ritzke)\
**Post date:** [January 2, 2014, 4:58pm UTC](https://community.wowza.com/t/why-no-b-frames-for-nvenc/40875/1 "2014-01-02T16:58:52Z")

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Dear Wowza,

NVENC supports B-Frames.

You support B-Frames using your “default” encoder.

Can we expect upcoming support of B-Frames in NVENC?

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**Author:** ![Richard\_Lanham](https://avatars.discourse-cdn.com/v4/letter/r/c68b51/32.png) [@Richard\_Lanham](https://community.wowza.com/u/Richard_Lanham)\
**Post date:** [January 3, 2014, 1:05am UTC](https://community.wowza.com/t/why-no-b-frames-for-nvenc/40875/2 "2014-01-03T01:05:12Z")

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There may be, depending on your system. Take a look at the [encoder params available in your system following this guide](https://www.wowza.com/docs/how-to-control-transcoded-video-with-video-encoding-parameters)

I’m not sure what the affect will be, but I see this param:

> INFO server comment - # long: advanced gop settings: use adaptive B-frames placement or not
> 
> INFO server comment - mainconcept.adaptive\_b\_frames: 1

These params are not documented, so you have to see what affect they have and if available on your system

Richard

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**Author:** ![Richard\_Lanham](https://avatars.discourse-cdn.com/v4/letter/r/c68b51/32.png) [@Richard\_Lanham](https://community.wowza.com/u/Richard_Lanham)\
**Post date:** [January 3, 2014, 6:23pm UTC](https://community.wowza.com/t/why-no-b-frames-for-nvenc/40875/3 "2014-01-03T18:23:30Z")

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Sorry, I did not know that param had been documented, missed it or forgot, in general they are not. I will ask around about NVENC b-frame support plans.

Richard

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**Author:** ![Jason\_Ritzke](https://avatars.discourse-cdn.com/v4/letter/j/ecc23a/32.png) [@Jason\_Ritzke](https://community.wowza.com/u/Jason_Ritzke)\
**Post date:** [January 3, 2014, 10:18am UTC](https://community.wowza.com/t/why-no-b-frames-for-nvenc/40875/4 "2014-01-03T10:18:42Z")

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Does this count as documentation?: [https://www.wowza.com/docs/how-to-configure-b-frame-support-when-using-wowza-transcoder](https://www.wowza.com/docs/how-to-configure-b-frame-support-when-using-wowza-transcoder)

> In Wowza Media Server® 3.5.0 and later, Wowza Transcoder AddOn supports bi-directional frames (B-frames) when using the default transcoder implementation and the Main Profile. B-frame generation is turned off by default. To enable B-frames for a given block, add the following parameter definition to the Video/Parameters container in the block in your transcoder template:
> 
> Code:
> 
> mainconcept.reordering\_delay
> 
> 2
> 
> Integer
> 
> The Value property specifies the number of B-frames to generate between each P-frame. The number of B-frames generated is always one less than the specified value. So for example, a value of 2 instructs the encoder to generate a single B-frame between each P-frame, a value of 3 instructs the encoder to generate two B-frames between each P-frame, and so on. A value of 1 instructs the encoder to generate zero B-frames between each P-frame, which effectively disables the feature.
> 
> Note: B-frame support is only available when using the default encoder implementation and the Main Profile. **_It’s not supported when using Intel Quick Sync, NVIDIA CUDA, or NVIDIA NVENC accelerated encoding._**

Emphasis mine. The log output you posted was for the “default” mainconcept encoder, which (as stated above) I already know can do b-frames.

This all leaves my original question unanswered, so I’ll ask again: “Can we expect upcoming support of B-Frames in NVENC?”

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<div class="post-metadata">

**Author:** ![Jason\_Ritzke](https://avatars.discourse-cdn.com/v4/letter/j/ecc23a/32.png) [@Jason\_Ritzke](https://community.wowza.com/u/Jason_Ritzke)\
**Post date:** [January 8, 2014, 9:26am UTC](https://community.wowza.com/t/why-no-b-frames-for-nvenc/40875/5 "2014-01-08T09:26:46Z")

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Thanks very much for that. I will eagerly await the reply (until then our Kepler cards produce somewhat inferior streams to those encoded by the CPU encoder, which makes them $800 paperweights).