Re: [ALSA-UTILS][PATCH] Add support for cplay and crecord

[Jaroslav Kysela <perex@perex.cz>]

Dne 5.3.2015 v 08:00 Vinod Koul napsal(a):
> On Wed, Mar 04, 2015 at 04:34:41PM +0000, Qais Yousef wrote:
>> On 03/04/2015 04:10 PM, Vinod Koul wrote:
>>> On Wed, Mar 04, 2015 at 03:36:00PM +0000, Qais Yousef wrote:
>>>> cplay and crecord use compress offload API to play and record compressed audio.
>>>>
>>>> They're based on cplay and crec from tinycompress library using LGPL license.
>>>>
>>>> For now cplay only supports playing mp3 files.
>>>>
>>>> Signed-off-by: Qais Yousef <qais.yousef@imgtec.com>
>>>> Cc: Takashi Iwai <tiwai@suse.de>
>>>> Cc: Vinod Koul <vinod.koul@intel.com>
>>>> Cc: Mark Brown <broonie@kernel.org>
>>>> ---
>>>> I renamed crec to crecord also to match aplay and arecord, hopefully
>>>> you don't mind Vinod.
>>> No thats fine..
>>>
>>>> This patch is dependent on my other patch that adds support for compress offload
>>>> to alsa-lib.
>>> And where is that, should have preceded this
>>
>> Hmm not sure what went wrong. I resent it. Seems I have some emailer
>> issues as I had this problem before.
>> Hopefully you received it now.
>>
>>>> I needed to include <sound/compress_params.h> in cplay.c and crec.c
>>>> but I couldn't find an example of any C file which directly includes <sound/*.h>
>>>> The norm seems to be to just include <alsa/asoundlib.h>. Do I need to
>>>> redefine structs from <sound/compress_params.h> to newly added <alsa/compress.h>?
>>>> <alsa/pcm.h> seems to redefine structs from <sound/asound.h>.
>>> These are kernel headers and should be in your include path if you have
>>> those installed
>>>> I could only test cplay but have no means to test crecord at the moment.
>>>>
>>>>  Makefile.am       |   3 +
>>>>  configure.ac      |   6 +-
>>>>  cplay/Makefile.am |  14 ++
>>>>  cplay/cplay.c     | 294 +++++++++++++++++++++++++++++++++++
>>>>  cplay/crec.c      | 449 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
>>>>  cplay/tinymp3.h   |  72 +++++++++
>>>>  6 files changed, 837 insertions(+), 1 deletion(-)
>>>>  create mode 100644 cplay/Makefile.am
>>>>  create mode 100644 cplay/cplay.c
>>>>  create mode 100644 cplay/crec.c
>>>>  create mode 100644 cplay/tinymp3.h
>>> Okay here is where we need discussion on the future course. If we do this
>>> then we end up in two code bases, something I would not encourage!
>>>
>>> On the other hand if we add the make file changes to tinycompress or if
>>> required split this into two, lib and tools and then package lib part into
>>> alsa-lib and players into tools, that way we can have single code base. That
>>> was my intent behind ensuring that this is dual licensed.
>>
>> I'm not sure I follow you completely here. You mean keep cplay and
>> crec in tinycompress with the dual licensing but only merge the lib
>> part (which my other patch does) into alsa-lib? For me having this
>> lib part into alsa-lib is the important bit. Moving crec and cplay
>> to alsa-utils was something I thought would be useful but maybe not.
> Not that
> 
> Since alsa splits lib and tools, in order to take this into alsa-libs we
> need to split tinycompress, to something like lib and tool part.
> 
> Then alsa-lib can import the lib part of tinycompress. Please note I am not
> saying we should copy or move code into alsa-lib.
> The reason for that is
> 1. copying code will cause more maintaince of same code in two places :(
> 2. moving into alsa-lib is not an option as existing users like android will
> suffer as they dont use alsa-lib
> 
> So I think, while building and packaging alsa-library and tools we can
> import the tinycompress using LGPL license and use that to give complete
> library on Linux to users
> 
> Takashi, can we get you blessing for this approach before we embark on this,
> or any other better ideas?

The problem is if the code is not duplicated, then the parts of the
alsa-lib binary will be dual-licenced. I don't think that it's the right
way.

And if the code is duplicated, then patch authors for all next updates
in both libraries (alsa-lib, tinycompress) must be asked for permissions
to change code licence for the merge to the second library.

I think that a plugin-style extension should be created here (so
tinycompress will be used at runtime as the dynamic library).

compress API -> tinycompress plugin -> tinycompress .so functions

This will allow us also to create another plugins in future.

					Jaroslav


-- 
Jaroslav Kysela <perex@perex.cz>
Linux Kernel Sound Maintainer
ALSA Project; Red Hat, Inc.