Hi, Thank you for the input. I think we have been neglecting digital-analog conversion issue until now. We don't have any experiences in broadcast a digital data over an analog channel. I think we should learn encoding, modulation and error correction now using google and others. That being said, I think this is not ALSA domain, however, any references and working example would be helpful for us. Thank you, Best Regards Arif On Sun, Aug 23, 2009 at 5:10 AM, James Courtier-Dutton < james.dutton@xxxxxxxxx> wrote: > 2009/8/22 arif setiawan <n.arif.setiawan@xxxxxxxxx>: > > Hi, > > > > We are working on audio processing (encryption-decryption) and audio will > be > > sent using radio. > > > > Our configuration is : > > > > Audio source - ALSA audio in - encryption - ALSA audio out - transmission > > over radio (now we still use audio cable) - ALSA audio in - decryption - > > ALSA audio out - speaker. > > > > So data will be sent through radio channel and its converted to analog > form > > by ALSA PCM during playback. We want to solve synchronization issue by > using > > data header so that we can decrypt correct data block. So far we still > > unable to verify that data we received in the decryption side is similar > to > > data that we sent from encryption box. Supposed that we filled buffer in > > encryption box with some values, when we check buffer in decryption box, > we > > can't get same data. Our guess that data somehow changed in > > digital-analog/analog-digital conversion or we might make mistakes in > > filling the buffer so data is not compatible with ALSA PCM. > > > > Any suggestion to solve this problem? > > > > Where is the conversion from digital to analogue on the output direction? > Where is the modulation and error correction happening on the radio > bit, in between the encrypt and decrypt steps. > You should probably do a test without the encrypt and decrypt stages, > and just ensure the input equals the output. > > Kind regards > > James > _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
