Hi Ross,
I found some infos from https://en.wikipedia.org/wiki/G.711 and
https://en.wikipedia.org/wiki/RTP_audio_video_profile.
Does ulaw only support 8KHz audio?
And from here:
G.711 passes audio signals in the range of 300–3400 Hz and samples them at the
rate of 8,000 samples per second, with the tolerance on that rate 50 parts per
million (ppm)
-> should we resample the audio source from 16KHz to 8KHz? then encode source
to be ulaw data?
Thanks a lot.
regards, eric, 12/18
________________________________________
從: Eric_Hsieh 謝國達 (HQ)
寄件日期: 2015年12月17日 下午 08:13
至: LIVE555 Streaming Media - development & use
主旨: 回覆: [Live-devel] H264 + ulaw streaming with audio vibration
Hi Ross,
Thanks for your quickly replay again.
Yes, according to your suggestion.
fDurationInMicroseconds = 256*1000000/ 16000 = 16000
The 16000 is same with what I mention early.
So, I am very confusing about the audio vibration.
Thanks a lot.
regards, eric, 12/17
________________________________________
從: live-devel <live-devel-boun...@ns.live555.com> 代表 Ross Finlayson
<finlay...@live555.com>
寄件日期: 2015年12月17日 下午 07:26
至: LIVE555 Streaming Media - development & use
主旨: Re: [Live-devel] H264 + ulaw streaming with audio vibration
> Each time, we will put 1024 bytes to ulaw encode and it produce 512 bytes
> ulaw data out.
> Then we copy 512 bytes to fTo and put 512 to fFrameSize.
> For fDurationInMicroseconds, we set 16000.
> I think it should be right. But I don’t know why 16K, stereo audio is not
> working.
Note that, for stereo, each sample is double the size of an audio sample.
Therefore, 1024 bytes of mono PCM is 512 samples, but 1024 bytes of stereo PCM
is 256 samples. Therefore, you should set
fDurationInMicroseconds = 512*1000000/<sampling-frequency>
for mono, and
fDurationInMicroseconds = 256*1000000/<sampling-frequency>
for stereo.
Ross Finlayson
Live Networks, Inc.
http://www.live555.com/
_______________________________________________
live-devel mailing list
live-devel@lists.live555.com
http://lists.live555.com/mailman/listinfo/live-devel
This electronic mail transmission is intended only for the named recipient. It
contains information which may be privileged,confidential and exempt from
disclosure under applicable law. Dissemination, distribution, or copying of
this communication by anyone other than the recipient or the recipient's agent
is strictly prohibited. If this electronic mail transmission is received in
error, Please notify us immediately and delete the message and all attachments
of it from your computer system. Thank you for your cooperation.
_______________________________________________
live-devel mailing list
live-devel@lists.live555.com
http://lists.live555.com/mailman/listinfo/live-devel
