Re: [ecasound] ecasound time accuracy

Humm .. well -a b 16 should be more than enough in accuracy (especially
@25fps) ... bit tired i guess :-)

Cheers

seb

Kai Vehmanen wrote:

> Hi,
>
> On Wed, 31 Aug 2005, sebastien Pastor wrote:
>
>> I am very new to ecasound and my use is a very basic one. I am trying
>> to use it to cut and join waves files. i need to have a "frame"
>> accuracy to stick to the video the wav is extracted from. strangely
>> when i use such a command :
>
>
> Ecasound is not necessary the best tool for the job as it always
> handles audio in blocks. For sample-accurate operations (like
> looping), Ecasound does offer the .ewf format, but this cannot, in its
> current form, be used for cut&paste use.
>
>> ecasound -i test.wav -o out.wav -t:104.36
>
>
> As a hack-solution, you can force ecasound to use one-sample blocks by
> adding -b:1 to the command-line.
>
>> out.wav appears to be 104.344 (from a get-length) (so after a while
>> on long videos the audio is drifting ...)
>
>
> This is a result of rounding 104.36 to the current blocksize. The
> default is -b:1024, which with 44.1kHz sampling freq results in
> 1024/44100*1000=23.22msec resolution. With -b:1, you already get 0.02msec
> resolution.
>
>> Could anyone tell me how i could achieve a "frame" accuracy ?
>
>
> With video frame rate of 30 (~33msec between video frames), -b:16
> (<1msec) or lower should be accurate enough.
>
> --
> links, my public keys, etc at http://eca.cx/kv
>
>

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Received on Thu Sep 1 04:15:05 2005