[FFmpeg-devel] [PATCH] pulse: set default frame_size to 4608

Michael Niedermayer michaelni at gmx.at
Thu Jan 2 23:26:49 CET 2014

On Thu, Jan 02, 2014 at 04:36:45PM +0100, Federico Simoncelli wrote:
> Given the current defaults (channels = 2, sample_rate = 48000) the
> frame_size is changed to 4608 in order to obtain whole numbers for
> frame_duration (both 16 and 24 bits_per_sample).
>  frame_duration = (frame_size * 1000000 * 8) /
>                   (sample_rate * channels * bits_per_sample)
> A message has been added to warn the user when the frame duration
> is not an integer.

the timebase should be changed to a multiple of the sample rate
see the avpriv_set_pts_info() call
that avoids the problem of the durations being not exactly

and the frame_size either should be "redefined" to mean samples
across all channels so that 8bit samples with 3 channels and a
frame size of 1024 means 3072 bytes

cutting frames between channels is quiet bad so a frame size
in bytes is problematic but if its kept in bytes then a default of
3360 should avoid the fractional durations with the changed timebase


Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

The misfortune of the wise is better than the prosperity of the fool.
-- Epicurus
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