The supported sound formats (and their proper file extensions) for the Tropo platform are as follows:
- 8kHz, 8bit u-law (wav or raw) (*.wav or *.ulaw)
- 8kHz, 8bit a-law (wav or raw) (*.wav or *.alaw)
- 8kHz, 8bit pcm (wav) (*.wav)
- 8khz, 16bit pcm (wav or raw) (*.wav or *.pcm)
- MS-GSM (wav) (*.wav)
- GSM 6.10 (raw) (*.gsm)
MP3 files will be automatically downsampled and converted due to limitations in telephony standards, so to control quality, it's always best to have your files in 8bit, 8Khz u-law format from the start.
Audio is streamed directly from the source - the file isn't downloaded first and then the then played.
Hosting Audio Files
Check out this page for more information on hosting audio files on the Tropo servers.