[Theora-dev] FPGA implementation

Andrey Filippov theora at elphel.com
Fri Jan 21 23:42:52 PST 2005

> Andrey Filippov wrote:
>>>>Then I used the virtually unmodified headers from the original file,
>>>> cut
>>>it where the actual frame data starts (I had to add one byte to the
>>> lacing
>>>numbers as my data was 0xe6a bytes long while the original - 2d2) and
>>>recalculated the check sum for the last page.
>> Correction - that was the total file size, frame is 0x35f
> The error message is somewhat misleading... the program is searching for
> the first data packet to be sure it has processed all of the headers. It
> can't find it, however, because the checksum you have computed for the
> first data page is incorrect. libogg computes a value of 0xB57CFB5C,
> while the file has 0xD7C61FBE stored in it.
> Also, strangely, libogg says there are 1151 (=894+257) bytes left in the
> buffer at this point, despite the fact that the page header+data only
> take up 894 bytes.

I fixed that file (the same link), and here is the extracted frame:


It is really ugly (it was supposed to be nearly monochrome 45 degree
gradient) - but it was the first time the data went all the way through
the FPGA!

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