[FFmpeg-devel] [PATCH] ffplay: add startup volume option

[Marton Balint]

On Sat, 24 Dec 2016, Ganesh Ajjanagadde wrote:

>
>
> 24.12.2016, 20:00, "Marton Balint" <cus at passwd.hu>:
>> On Thu, 22 Dec 2016, gajjanag at yandex.com wrote:
>>
>>>  From: Ganesh Ajjanagadde <gajjanag at alum.mit.edu>
>>>
>>>  Fixes Ticket 5389.
>>>
>>>  Signed-off-by: Ganesh Ajjanagadde <gajjanag at alum.mit.edu>
>>>  ---
>>>  doc/ffplay.texi | 4 ++++
>>>  ffplay.c | 10 +++++++++-
>>>  2 files changed, 13 insertions(+), 1 deletion(-)
>>>
>>>  diff --git a/doc/ffplay.texi b/doc/ffplay.texi
>>>  index 073b457256..378a229d67 100644
>>>  --- a/doc/ffplay.texi
>>>  +++ b/doc/ffplay.texi
>>>  @@ -62,6 +62,10 @@ see @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1)
>>>  Seek by bytes.
>>>  @item -nodisp
>>>  Disable graphical display.
>>>  + at item -volume
>>>  +Set the startup volume. 0 means silence, 100 means no volume reduction or
>>>  +amplification. Negative values are treated as 0, values above 100 are treated
>>>  +as 100.
>>>  @item -f @var{fmt}
>>>  Force format.
>>>  @item -window_title @var{title}
>>>  diff --git a/ffplay.c b/ffplay.c
>>>  index 911fd7f947..de603c0a27 100644
>>>  --- a/ffplay.c
>>>  +++ b/ffplay.c
>>>  @@ -322,6 +322,7 @@ static int subtitle_disable;
>>>  static const char* wanted_stream_spec[AVMEDIA_TYPE_NB] = {0};
>>>  static int seek_by_bytes = -1;
>>>  static int display_disable;
>>>  +static int startup_volume = 100;
>>>  static int show_status = 1;
>>>  static int av_sync_type = AV_SYNC_AUDIO_MASTER;
>>>  static int64_t start_time = AV_NOPTS_VALUE;
>>>  @@ -3105,7 +3106,13 @@ static VideoState *stream_open(const char *filename, AVInputFormat *iformat)
>>>      init_clock(&is->audclk, &is->audioq.serial);
>>>      init_clock(&is->extclk, &is->extclk.serial);
>>>      is->audio_clock_serial = -1;
>>>  - is->audio_volume = SDL_MIX_MAXVOLUME;
>>>  + if (startup_volume < 0)
>>>  + av_log(NULL, AV_LOG_WARNING, "-volume=%d < 0, setting to 0\n", startup_volume);
>>>  + if (startup_volume > 100)
>>>  + av_log(NULL, AV_LOG_WARNING, "-volume=%d > 100, setting to 100\n", startup_volume);
>>>  + startup_volume = av_clip(startup_volume, 0, 100);
>>>  + startup_volume = av_clip(SDL_MIX_MAXVOLUME * startup_volume / 100.0, 0, SDL_MIX_MAXVOLUME);
>>
>> Any reason you use 100.0 here instead of a simple integer (100)?
>
> Nothing really, I assumed (incorrectly) that double to int cast does rounding instead of truncation,
> which happens with integer division.
> On the other hand, the difference here between rounding and truncation is < 1%.
> Whatever you prefer, i.e can lrint it to get better rounding, or change to 100 and not bother.

I'd simply use 100 and not bother.

Thanks,
Marton