An Implementation of Real-Time Audio Monitoring in Network Camera - Multimedia and Signal Processing - page 419

audio sample rate is typically set to 44.1 KHz at bit rate 64 kbps per channel, audio
and video can be monitored normally and their synchronization performs well.
(2)When audio sample rates in ALSA settings and AAC encoding settings are differ-
ent, sound will be played by publisher at a lower or faster speed than normal. (3)If
AAC sequence header is not sent, audio can't be played correctly by publisher.
(4)Under the condition of good network status, the whole delay of capturing, encod-
ing and transmitting data can be optimized within 3 seconds.

5 Conclusions

Fundamental principles of Network camera as well as software and hardware frame-
work based on Ambarella A5s platform are briefly analyzed in this paper. Audio
module of network camera is implemented independently. Furthermore, RTMP is
used to transmit audio and video data to RTMP server Red5 for monitoring test.

Acknowledgements. This work is supported by National Basic Research Program of
China 2012CB315904, NSFC (Natural Science Foundation of China) 61179028,
Guangdong Natural Science Fund 2011010000923, Shenzhen Basic Research
201005260234A, 201104210120A, Shenzhen Industry 201006110044A.

References

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