Help in understanding SND_PCM_TSTAMP_ENABLE mode snd_pcm_htimestamp function

Help in understanding SND_PCM_TSTAMP_ENABLE mode snd_pcm_htimestamp function

[divya v]

Hi,

I am looking for a method to maintain timestamps for every sample read or
written.
I noticed the *SND_PCM_TSTAMP_ENABLE mode. But the description mentions - ""
*pdate timestamp at every hardware position update"
Doe this mean that the when snd_pcm_htimestamp() is issued, we will get the
last hardware update timestamp or does it mean that it will fetch the
timestamp of that particular sample?

Thanks,
Divya

Re: Help in understanding SND_PCM_TSTAMP_ENABLE mode snd_pcm_htimestamp function

[Clemens Ladisch]

divya v wrote:
> I am looking for a method to maintain timestamps for every sample read or
> written.

ALSA does not have timestamps for every sample.

> I noticed the *SND_PCM_TSTAMP_ENABLE mode. But the description mentions - ""
> *pdate timestamp at every hardware position update"
> Doe this mean that the when snd_pcm_htimestamp() is issued, we will get the
> last hardware update timestamp

Yes, this is what the documentation says.

> or does it mean that it will fetch the timestamp of that particular
> sample?

Yes; it will fetch the timestamp of the particular sample that is
returned in "avail".


Regards,
Clemens