Currently, There are two drivers that support ISDB-T: dibcom dib0700 and pt1 driver.
The dib0700 implements the new DVBS2API to allow finer control at the ISDB-T parameters.
How to make it work with the current dvb-apps version
Some changes are needed at dvb-apps in order to support the new DVBS2API parameters for ISDB-T. While those changes aren't implemented there and at the userspace apps, you need to use the DVB-T format.
In the case of ISDB-T, the current implementations (Brazil and Japan) use 6 MHz bandwidth with the same ISDB-T Frequency Table. In the future, this is likely to change.
For the device to work, the first step is to seek for the existing channels. This is done by running the 'scan' application:
scan FrequencyTable >channels.conf
Then, a DVB-T userspace application can be used to play the stream. In the case of Brazil, the application needs to support H.264 for video, HE-AAC for audio, and PMT tables at the mpeg-ts. Currently, only vlc and the newest development versions of mplayer are known to support. However, some stream types are known to not work with none of those two applications, due to some existing bugs.