The TAP and the patch accelerate USB transfers by suppressing the calculation of the CRC16 checksum for data blocks being transferred from PVR to PC.
Results measured with a 1617870848-byte file transferred from a TF5000PVR and a 2-year old PC (Athlon) running Windows XP:
- w/o modification: 725265 msec => 2.2 MB/s
- with modification: 479344 msec => 3.37 MB/s
In order to benefit from the USB Accelerator you should either install the patch or run the TAP once before starting to transfer the data after restart.
Both do basically the same thing. The patch modifies the firmware permanently. The TAP modifies the firmware in the RAM temporarily (i.e. until next restart).
The modified firmware can only be deployed with tools tolerating the protocol deviation mentioned above. Currently the following tools can be used with modified firmware:
- Altair with a patched TfDll (included, the original is dated April 29, 2005)
- MPEG Streamclip (MacOS X)
- FTP Server for Topfield (Aldarin's Topfield Place)
- TF-Addon (Aldarin's Topfield Place)
- Easy PVR Advanced API (Aldarin's Topfield Place)
- TF - Copy (Aldarin's Topfield Place)
The CRC16 calculation is dispensable because USB chips ensure the data integrity by deploying the CRC16.
The patched TfDll also accepts data packets with valid CRC16.
The modification is only applied to transfers from PVR to PC. The opposite direction remains as is.
The use of the software is done at your own discretion and risk and with agreement that you will be solely responsible for any damage to your computer system or loss of data that results from such activities. The author assumes no responsibility for errors.
Even though many tests have shown that the transferred data is not corrupted it is still possible that the transferred data may be unusable.
USB Accelerator 1.0