Re: [pulseaudio-discuss] Bluetooth A2DP aptX codec quality
Hi Arun, On Tue, Sep 18, 2018 at 9:02 PM, Arun Raghavan wrote: > On Wed, 12 Sep 2018, at 4:12 PM, Pali Rohár wrote: >> Hello! >> >> I would like to let you know that Serge from soundexpert.org did in last >> month some research on aptX and its quality. Detailed article is on the >> following website, specially see parts added around "August 2018": >> >> http://soundexpert.org/news/-/blogs/audio-quality-of-bluetooth-aptx >> >> >> Conclusions: >> >> aptX codec used in BT applications is no better than SBC@328. Despite >> slightly lower algorithmic delay of aptX both SBC and aptX codecs >> provide the same 100-150ms latency in real-life BT applications. >> >> If you hear the difference between SBC and aptX in some BT product, >> there can be only two explanations - placebo effect or using SBC in >> Middle or Low Quality modes. >> >> AptX is just a copper-less overpriced audio cable. >> >> aptX HD is high-bitrate version of aptX. It has clearly noticeable >> increase in sound quality (not dramatic though taking into account the >> increase in bitrate) >> >> >> And it just confirms my own testing. Whatever I did I was not able to >> either hear or see difference between aptX and SBC encoded-->decoded >> audio. >> >> I had discussion with Serge and there are some ideas which Linux >> Bluetooth A2DP software could supports: >> >> 1) Allow user to specify SBC codec quality. In most cases, including >> pulseaudio, SBC quality is chosen either to middle or low, not to >> maximum bitpool. In some cases SBC at high quality can provide better >> quality as aptX and more important -- SBC is supported by all headsets. >> >> 2) Show user current SBC codec quality. So user would know what was >> chosen and what should expect. I was told that Windows's Toshiba >> bluetooth stack has support for this indication. >> >> 3) In some cases SBC SNR bit allocation method can provide better >> quality as SBC loudness method. > > Thanks for sharing, this is very interesting. > >> So then I could ask question: >> >> 1) What to do with aptX? It is really useful for users to have it in >> Linux & pulseaudio? Because it looks like that the only thing which it >> has better is lower latency. But can pulseaudio on Linux system really >> achieve it? > > What would prevent us from doing so? > >> 2) Should we rather look at increasing quality of SBC codec in >> pulseaudio? And if yes, how should be quality of SBC configured? Via >> profiles? Or to invent some new protocol options? Can we increase >> default SBC bitpool allocation? > > My preference is to not expose things to the user but try to move towards > >> 3) If aptX is decided as useless, what about aptX HD codec? aptX HD >> codec is supported by less products (currently I do not own any), but >> this one may provide better quality as SBC according to that research. > > Right, could still be worth it indeed. > >> PS: That aptX research is the first and the only one about which I know. >> All other information about quality or other details which I found on >> internet are just marking informations. > > In general, it seems the work to support other codecs could still be valuable > for AAC and maybe in the future, LDAC? Is anyone aware of a similar > comparison for the either of these codecs? > > AAC is still interesting for passthrough media, of course (I hope to have > more on the ability to support that in coming weeks/months). Any objective > information on LDAC would be interesting too. Afaik Android supports LDAC so at least for headset/carkits using PA that would be a good addition, though it requires even higher bitrate: https://www.androidauthority.com/sony-ldac-codec-790690/ -- Luiz Augusto von Dentz ___ pulseaudio-discuss mailing list pulseaudio-discuss@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/pulseaudio-discuss
Re: [pulseaudio-discuss] Bluetooth A2DP aptX codec quality
On Wed, 12 Sep 2018, at 4:12 PM, Pali Rohár wrote: > Hello! > > I would like to let you know that Serge from soundexpert.org did in last > month some research on aptX and its quality. Detailed article is on the > following website, specially see parts added around "August 2018": > > http://soundexpert.org/news/-/blogs/audio-quality-of-bluetooth-aptx > > > Conclusions: > > aptX codec used in BT applications is no better than SBC@328. Despite > slightly lower algorithmic delay of aptX both SBC and aptX codecs > provide the same 100-150ms latency in real-life BT applications. > > If you hear the difference between SBC and aptX in some BT product, > there can be only two explanations - placebo effect or using SBC in > Middle or Low Quality modes. > > AptX is just a copper-less overpriced audio cable. > > aptX HD is high-bitrate version of aptX. It has clearly noticeable > increase in sound quality (not dramatic though taking into account the > increase in bitrate) > > > And it just confirms my own testing. Whatever I did I was not able to > either hear or see difference between aptX and SBC encoded-->decoded > audio. > > I had discussion with Serge and there are some ideas which Linux > Bluetooth A2DP software could supports: > > 1) Allow user to specify SBC codec quality. In most cases, including > pulseaudio, SBC quality is chosen either to middle or low, not to > maximum bitpool. In some cases SBC at high quality can provide better > quality as aptX and more important -- SBC is supported by all headsets. > > 2) Show user current SBC codec quality. So user would know what was > chosen and what should expect. I was told that Windows's Toshiba > bluetooth stack has support for this indication. > > 3) In some cases SBC SNR bit allocation method can provide better > quality as SBC loudness method. Thanks for sharing, this is very interesting. > So then I could ask question: > > 1) What to do with aptX? It is really useful for users to have it in > Linux & pulseaudio? Because it looks like that the only thing which it > has better is lower latency. But can pulseaudio on Linux system really > achieve it? What would prevent us from doing so? > 2) Should we rather look at increasing quality of SBC codec in > pulseaudio? And if yes, how should be quality of SBC configured? Via > profiles? Or to invent some new protocol options? Can we increase > default SBC bitpool allocation? My preference is to not expose things to the user but try to move towards > 3) If aptX is decided as useless, what about aptX HD codec? aptX HD > codec is supported by less products (currently I do not own any), but > this one may provide better quality as SBC according to that research. Right, could still be worth it indeed. > PS: That aptX research is the first and the only one about which I know. > All other information about quality or other details which I found on > internet are just marking informations. In general, it seems the work to support other codecs could still be valuable for AAC and maybe in the future, LDAC? Is anyone aware of a similar comparison for the either of these codecs? AAC is still interesting for passthrough media, of course (I hope to have more on the ability to support that in coming weeks/months). Any objective information on LDAC would be interesting too. Cheers, Arun ___ pulseaudio-discuss mailing list pulseaudio-discuss@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/pulseaudio-discuss
Re: [pulseaudio-discuss] Bluetooth A2DP aptX codec quality
On Fri, 2018-09-14 at 15:43 +0300, ValdikSS wrote: > On 13/09/2018 11:23, Tanu Kaskinen wrote: > > > > How is the bitrate calculated? I'd like to write a section on the > > Bluetooth wiki page[1] that explains the SBC codec with a table showing > > how the different parameters affect the bitrate. > > > > [1] > > https://www.freedesktop.org/wiki/Software/PulseAudio/Documentation/User/Bluetooth/ > > > > Bitrate formula could be found in A2DP specification: > https://www.bluetooth.org/DocMan/handlers/DownloadDoc.ashx?doc_id=303201 > Page 70. > > Here's a convenient calculator: > https://btcodecs.valdikss.org.ru/sbc-bitrate-calculator/ Thanks for the links! The calculator is great! -- Tanu https://www.patreon.com/tanuk https://liberapay.com/tanuk ___ pulseaudio-discuss mailing list pulseaudio-discuss@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/pulseaudio-discuss
Re: [pulseaudio-discuss] [PATCH v2 2/2] Bluetooth A2DP aptX codec support
Hi Pali, On Mon, Sep 17, 2018 at 3:27 PM, Tanu Kaskinen wrote: > On Thu, 2018-09-13 at 11:12 +0200, Pali Rohár wrote: >> On Wednesday 05 September 2018 13:57:08 Tanu Kaskinen wrote: >> > > + Bluetooth A2DP aptX codec (optional) ### >> > > + >> > > +AC_ARG_ENABLE([aptx], >> > > +AS_HELP_STRING([--disable-aptx],[Disable optional bluetooth A2DP >> > > aptX codec support (via libopenaptx)])) >> > > + >> > > +AS_IF([test "x$HAVE_BLUEZ_5" = "x1" && test "x$enable_aptx" != "xno"], >> > > +[AC_CHECK_HEADER([openaptx.h], >> > > +[AC_CHECK_LIB([openaptx], [aptx_init], [HAVE_OPENAPTX=1], >> > > [HAVE_OPENAPTX=0])], >> > > +[HAVE_OPENAPTX=0])]) >> > >> > Have you considered providing a .pc file? Now we have to hardcode the >> > openaptx specific CFLAGS and LIBADD for libbluez5-util. If you ever >> > need to add new flags, all openaptx users need to update their build >> > systems. Also, if the library is installed to a non-standard location, >> > the .pc file can set the -L and -I flags to point to the right place. >> >> Intension is that library is small and does not need any special cflags >> or ldflags. So .pc file is not needed at all. And if library or include >> file is in non-standard location then user really need to specify where >> it is. But same argument can be used when .pc file is in non-standard >> location. User again need to do some magic. Long term I think it is best to use autotools to properly generate the .pc file, etc, otherwise it might be difficult for distros to pick this up. I might be able to help you with that if you are willing to accept patches. -- Luiz Augusto von Dentz ___ pulseaudio-discuss mailing list pulseaudio-discuss@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/pulseaudio-discuss
Re: [pulseaudio-discuss] Adopting a Code of Conduct
Hi Arun, On Mon, Sep 17, 2018 at 3:58 PM, Arun Raghavan wrote: > Hi everyone, > This has been on my mind for a while, and seeing the freedesktop.org and > Linux kernel projects finally take it up, I'd like for us to adopt a code of > conduct as well. > > The wording in the Contributor Covenant > (https://www.contributor-covenant.org/) seems to be succinct but thorough in > summarising what I'd like our code of conduct to be (i.e. "be excellent to > each other"), while also laying out explicitly who can be approached for > specific issues and also explicitly who is responsible of making the > community a fostering and welcoming space (namely, the maintainers). > > I'll send out an MR for this in a bit, but thought I'd kick off a thread for > discussion if needed. Great initiative, even though Ive always got very polite, and productive, responses in the list adopting a code of conduct should hopefully re-enforce how we interact with each other. -- Luiz Augusto von Dentz ___ pulseaudio-discuss mailing list pulseaudio-discuss@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/pulseaudio-discuss
