~sircmpwn/public-inbox

8 4

Uses for HDCP other than DRM

Simon Farnsworth
Details
Message ID
<F8013D4C-4E17-46D4-96FA-2C3235A3539A@farnz.org.uk>
DKIM signature
missing
Download raw message
Hello Drew,

I think you miss an important point about HDCP - there already exist devices that will simply refuse to work properly (or at least to their full extent) if the source does not provide a HDCP scrambled signal.

For example, the specification for Dolby TrueHD recommends that sinks refuse to decode TrueHD audio if it's supplied unencrypted - it must be supplied with HDCP "protection", else it's an invalid bitstream and cannot be decoded.

I have also had the misfortune of encountering all-in-one "home cinema" kits that are soft-limited to stereo 48 kHz 16 bit audio if the source is not HDCP scrambled; the only ways around this are to disable surround sound and hires audio, or accept that the system is silent and the troubleshooting flags this as a "faulty source device".

By implementing HDCP support, for scrambling a framebuffer that's already visible to the system software, Collabora make it possible for me to send hires audio to such a device - or to implement my own MLP encoder and send my own TrueHD audio stream to a receiver. I can't do this if people refuse to implement HDCP at all.

Simon
Details
Message ID
<BXLVD2YKRJ8V.2HELSU3QQWBTG@homura>
In-Reply-To
<F8013D4C-4E17-46D4-96FA-2C3235A3539A@farnz.org.uk> (view parent)
DKIM signature
missing
Download raw message
Hey Simon, good point, but I don't think you should be rewarding this
behavior by spending money on products like this.
Simon Farnsworth
Details
Message ID
<02043837-786F-4F59-9BE6-F5618C3A07AD@farnz.org.uk>
In-Reply-To
<BXLVD2YKRJ8V.2HELSU3QQWBTG@homura> (view parent)
DKIM signature
missing
Download raw message
> On 10 Oct 2019, at 14:13, Drew DeVault <sir@cmpwn.com> wrote:
> 
> Hey Simon, good point, but I don't think you should be rewarding this
> behavior by spending money on products like this.

OK, so you're saying that Free Software should be excluded from encoding hires audio to send to Dolby TrueHD receivers, and that where there's a simple software workaround (not DRM - there's no scrambled framebuffer here, or chain of trust required to enable HDCP), people should be forced to buy new hardware that doesn't have this misfeature?

Also, there's no way to tell that the hardware *has* this misfeature until you buy it; by that point, it's too late to not reward this behaviour, as you already own the kit, and it's not faulty.

Simon
Details
Message ID
<BXLWRSTRBL2E.1XCYSBN2GQ505@homura>
In-Reply-To
<02043837-786F-4F59-9BE6-F5618C3A07AD@farnz.org.uk> (view parent)
DKIM signature
missing
Download raw message
Yes, that's what I'm saying.
Details
Message ID
<77F66D2D-2AA3-4698-8489-26AAFCC4BF61@gmail.com>
In-Reply-To
<02043837-786F-4F59-9BE6-F5618C3A07AD@farnz.org.uk> (view parent)
DKIM signature
missing
Download raw message
Any reasonable seller would let you return it within a reasonable period of time to test the equipment.

> On Oct 10, 2019, at 09:16, Simon Farnsworth <simon@farnz.org.uk> wrote:
> 
> 
>> 
>> On 10 Oct 2019, at 14:13, Drew DeVault <sir@cmpwn.com> wrote:
>> 
>> Hey Simon, good point, but I don't think you should be rewarding this
>> behavior by spending money on products like this.
> 
> OK, so you're saying that Free Software should be excluded from encoding hires audio to send to Dolby TrueHD receivers, and that where there's a simple software workaround (not DRM - there's no scrambled framebuffer here, or chain of trust required to enable HDCP), people should be forced to buy new hardware that doesn't have this misfeature?
> 
> Also, there's no way to tell that the hardware *has* this misfeature until you buy it; by that point, it's too late to not reward this behaviour, as you already own the kit, and it's not faulty.
> 
> Simon
Simon Farnsworth
Details
Message ID
<99B24A13-A73C-4864-B1A5-F4EF79A3D536@farnz.org.uk>
In-Reply-To
<77F66D2D-2AA3-4698-8489-26AAFCC4BF61@gmail.com> (view parent)
DKIM signature
missing
Download raw message
Private sellers tend not to - and nor do big box retailers, where the product is no longer as-new, and yet is fully functional as far as they can test.

This is a repeat, BTW, of the old problem we used to face in the Free Software world with NICs where two completely different chipsets would be sold under the same name; retailers didn't accept returns then because the card worked for the purpose it was sold for.

Simon

> On 10 Oct 2019, at 15:34, Garrison Taylor <garrisontaylor@gmail.com> wrote:
> 
> Any reasonable seller would let you return it within a reasonable period of time to test the equipment.
> 
>> On Oct 10, 2019, at 09:16, Simon Farnsworth <simon@farnz.org.uk> wrote:
>> 
>> 
>>> 
>>> On 10 Oct 2019, at 14:13, Drew DeVault <sir@cmpwn.com> wrote:
>>> 
>>> Hey Simon, good point, but I don't think you should be rewarding this
>>> behavior by spending money on products like this.
>> 
>> OK, so you're saying that Free Software should be excluded from encoding hires audio to send to Dolby TrueHD receivers, and that where there's a simple software workaround (not DRM - there's no scrambled framebuffer here, or chain of trust required to enable HDCP), people should be forced to buy new hardware that doesn't have this misfeature?
>> 
>> Also, there's no way to tell that the hardware *has* this misfeature until you buy it; by that point, it's too late to not reward this behaviour, as you already own the kit, and it's not faulty.
>> 
>> Simon
Simon Farnsworth
Details
Message ID
<C9F70ADC-5309-4545-9BA0-492294D04E82@farnz.org.uk>
In-Reply-To
<BXLWRSTRBL2E.1XCYSBN2GQ505@homura> (view parent)
DKIM signature
missing
Download raw message
What other fields of endeavour do you think that Free Software should be excluded from?

Obviously, private repo hosting (GitHub, Bitbucket etc) has to be something I refuse to pay for by the same logic, as it's possible to use private repo hosting for completely closed software.

Any others?

Simon 

> On 10 Oct 2019, at 15:19, Drew DeVault <sir@cmpwn.com> wrote:
> 
> Yes, that's what I'm saying.
Details
Message ID
<9E10087C-E6B8-493C-98DB-7A4CF0F3DF72@cosmoborsky.com>
In-Reply-To
<C9F70ADC-5309-4545-9BA0-492294D04E82@farnz.org.uk> (view parent)
DKIM signature
missing
Download raw message

On October 10, 2019 2:40:05 PM UTC, Simon Farnsworth <simon@farnz.org.uk> wrote:
>What other fields of endeavour do you think that Free Software should
>be excluded from?

Simon, I believe you missed the point.

The biggest issue is proprietary protocols (and software) starting to make their way to FOSS.

>Obviously, private repo hosting (GitHub, Bitbucket etc) has to be
>something I refuse to pay for by the same logic, as it's possible to
>use private repo hosting for completely closed software.

These services are irrelevant as Git is FOSS in itself.
The way you compare Git to these services is like using an HDMI encoder on the output of your Wayland fb.

There /are/ HDMI encoders out there that fit this purpose, however I have never tested one (as I don't have a need yet).
Simon Farnsworth
Details
Message ID
<41F5B148-E4AF-43F8-9416-560F09637B73@farnz.org.uk>
In-Reply-To
<9E10087C-E6B8-493C-98DB-7A4CF0F3DF72@cosmoborsky.com> (view parent)
DKIM signature
missing
Download raw message
> On 12 Oct 2019, at 05:36, Cosmo Borsky <me@cosmoborsky.com> wrote:
> 
> 
> 
> On October 10, 2019 2:40:05 PM UTC, Simon Farnsworth <simon@farnz.org.uk> wrote:
>> What other fields of endeavour do you think that Free Software should
>> be excluded from?
> 
> Simon, I believe you missed the point.
> 
> The biggest issue is proprietary protocols (and software) starting to make their way to FOSS.
> 

HDMI is inherently a proprietary protocol - you have to pay HDMI Licensing LLC to use it on your device. If that's the issue, then HDMI is the core problem, not HDCP.

Note that you have to pay HDMI Licensing LLC just to get legitimate access to the HDMI specification - whereas HDCP is available for free at https://www.digital-cp.com/hdcp-specifications, and you only pay to use HDCP, not to understand it.

So, if that's the issue, then all HDMI support is the problem, not just HDCP.

>> Obviously, private repo hosting (GitHub, Bitbucket etc) has to be
>> something I refuse to pay for by the same logic, as it's possible to
>> use private repo hosting for completely closed software.
> 
> These services are irrelevant as Git is FOSS in itself.
> The way you compare Git to these services is like using an HDMI encoder on the output of your Wayland fb.
> 
> There /are/ HDMI encoders out there that fit this purpose, however I have never tested one (as I don't have a need yet).

There are plenty of HDMI encoders out there - there's three built into the Intel chipset on the machine I'm typing this on, all of which have already paid the license fees for HDMI and HDCP.

Given that I have a device that supports HDCP encoding, and a device that supports HDCP decoding, and that by buying a device that supports HDCP at all, I've already paid for it, why should I not use Free Software with HDCP? Because proprietary users of HDCP might use it for Bad Things - but if that's the case, the same applies to any private git hosting.

Further, there is functionality in equipment that is specification-locked to require HDCP (Dolby TrueHD requires it to receive TrueHD over HDMI); why should I be banned from using that functionality completely if I use Free Software? Why shouldn't I be allowed to use FFmpeg to encode my work to TrueHD (or even implement Dolby Atmos!) and then send that over HDMI to a TrueHD receiver?

Simon
Export thread (mbox)