Hi all, I have developed MP3 Audio Decoder on windows NT platform . Previously i used to put the ouptput of Decoder i.e, PCM samples into the file and play it through the Cool Edit software. Now i am trying to play the PCM samples directly through the speaker.Eeven though i have suceeded to quite an extent, i am facing some problems which are as follows: Issues encountered when an mp3 file stored in the hard disk is decoded and the PCM samples are directly given to the speakers: 1.The maximum size of the file should be 4 MB so that the song will be played without any disturbances. 2.If the bitrate and the sampling frequency is other than 128 kbps and 44.1kHz respectively then disturbance will be there irrespective of the mp3 file size. 3.While playing the RAM usage increases proportionately with time. 4.Even the output dec file which is generated while playing directly, contains junk values at irregular intervals which otherwise would have been absent in case of our offline decoder (i.e.when the pcm samples were being written to a file So please help me regarding this matter. Thanx in advance Regards, Raghuram.
how to drive pcm samples directly to speaker
Started by ●September 19, 2002
Reply by ●September 19, 20022002-09-19
Hi Raghuram, especially the fourth issue makes me think your buffering logic is probably flawed. I'd suggest relying on a library for sound output. E.g., PortAudio supports MME and ASIO on NT: http://www.portaudio.com/ > Hi all, > > I have developed MP3 Audio Decoder on windows NT platform . > Previously i used to put the ouptput of Decoder i.e, PCM samples into > the file and play it through the Cool Edit software. Now i am trying > to play the PCM samples directly through the speaker.Eeven though i > have suceeded to quite an extent, i am facing some problems which are > as follows: > > > Issues encountered when an mp3 file stored in the hard disk is > decoded and the PCM samples are directly given to the speakers: > > 1.The maximum size of the file should be 4 MB so that the song will > be played without any disturbances. > > 2.If the bitrate and the sampling frequency is other than 128 kbps > and 44.1kHz respectively then disturbance will be there irrespective > of the mp3 file size. > > 3.While playing the RAM usage increases proportionately with time. > > 4.Even the output dec file which is generated while playing directly, > contains junk values at irregular intervals which otherwise would > have been absent in case of our offline decoder (i.e.when the pcm > samples were being written to a file > > So please help me regarding this matter. > > Thanx in advance > Regards, > Raghuram.