[FFmpeg-devel] [PATCH] libavdevice/decklink: 32 bit audio support

[Dave Rice]

> On Oct 17, 2017, at 11:48 AM, Paul B Mahol <onemda at gmail.com> wrote:
> 
> On 10/17/17, Moritz Barsnick <barsnick at gmx.net> wrote:
>> On Tue, Oct 17, 2017 at 11:12:46 -0400, Dave Rice wrote:
>> 
>>> Thanks for pointing me in the right direction. I am attaching an
>>> updated patch below; however, after removing my 16/32 and using the
>>> enumeration method (with the patch below), it accepts any value
>>> between AUDIO_BITDEPTH_LOWEST and AUDIO_BITDEPTH_NB-1 (16 and 32).
>>> When I enter any value from 17 through 31 then the output is still in
>>> pcm_s16le, however the resulting audio is slow and choppy (I'm
>>> guessing from the pkt.size line). Am I missing some method to say
>>> that the enumeration list is restrictive?
>> 
>> Yes, that was exactly the oversight I had. The const'ified option now
>> takes those strings, but also numbers within the range. So the option
>> value "16" will be either "16" (string) or 16 (or integer), "17" will
>> be interpreted as integer 17 (and still valid thanks to the range), and
>> so on. My bad.
>> 
>> So I guess it's stupid to use a string enum to represent a number
>> value. You could properly restrict its use to the enumerated values if
>> they were subsequent (i.e. 0, 1), and perhaps strings with letters for
>> the enumerated options. But that's totally unintuitive. It would result
>> in (auto doc):
>> 
>>  -audio_depth      <int>         .D...... audio bitdepth (from 0 to 1)
>> (default 16bits)
>>     16bits                       .D......
>>     32bits                       .D......
>> 
>> and you could use it with either
>>  -audio_depth 0 # 16 bits
>>  -audio_depth 1 # 32 bits
>>  -audio_depth 16bits # 16 bits
>>  -audio_depth 32bits # 16 bits
>> but not
>>  -audio_depth 16
>> 
>> Horrible!
>> 
>> Your original version was most intuitive, IMHO. Sorry for explaining
>> the concept. ;-) It fits well for anything representable by strings,
>> not numbers.
> 
> Hmm, first patch might be enough.

Sounds good to me. Unless anyone prefers "-audio_depth thirtytwo" :-D
Dave Rice