[Libav-user] setting raw alsa pkt size

daggs daggs at gmx.com
Wed May 13 21:11:58 CEST 2015

Greetings Nicolas,

> Sent: Wednesday, May 13, 2015 at 1:40 PM
> From: "Nicolas George" <george at nsup.org>
> To: "This list is about using libavcodec, libavformat, libavutil, libavdevice and libavfilter." <libav-user at ffmpeg.org>
> Subject: Re: [Libav-user] setting raw alsa pkt size
> Le quartidi 24 floréal, an CCXXIII, Carl Eugen Hoyos a écrit :
> > Which means that A/V sync is impossible to keep, or 
> > do I miss something?
> Why do you think that? Whether the captures happen in separate threads or
> not, A-V sync is made difficult by the latency in each part of the system,
> especially the buffer of the audio device, but the lavd demuxers account for
> that and provide accurate timestamps. As long as the timestamps are based on
> the same clock (which they are in this particular instance), A-V sync is
> guaranteed.
can one define that "same clock"?

> > > but for audio I get a whopping 939834256 which 
> > > translates into 939 mb which is unacceptable for me.
> > 939MB per hour? Or per day?
> > This is the maximum alsa buffer size on your system.
> daggs: how do you measure that frame size? You should not need to.
looking at AVPacket, I see that it's has two fields, uint8_t *data and int size.
I assume that these holds the actual data, thus I print the size var and get the size above.

I want to lower the size to a more logical size.

having a single av pkt that takes about 1 gb of ram isn't good for me. I don't want to kill all the memory.

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