[gst-embedded] Calculating RAW Audio Buffer Size

[Michael Smith]

On Tue, Dec 23, 2008 at 9:12 AM, Sameer Naik
<sameer.subscriptions at damagehead.com> wrote:
> Hi,
> I am writing a gstreamer plugin in which i  need to calculate the raw audio
> buffer size for a give sample rate, channels, etc.
>
> for example if i have a mp3 frame with the following parameters:
> bitrate:                        320Kbps
> sampling rate:  48000Hz
> Channels:               2
>
> How can i calculate the buffer size that would be required by the output buffer
> to store the raw decoded data for this frame? basically what is the formula
> for this calculation?

size = samples_per_frame * channels * width

You give channels here, so that's easy. Width depends on the format
you're decoding to - e.g. if you have 32 bit floating point samples,
width is 4 (bytes). If you have 16 bit samples, it's 2.

samples_per_frame is mp3-specific. It's either 1152 or 576, depending
on the bitrate (and layer, and whether it's using the "mpeg 2.5"
extensions. For 320 kbps mp3, it's 1152.

So: size = 1152 * 2 * sample_width

Mike