[MPlayer-users] Possibly incorrect waveheader in -ao pcm
descentspb at gmail.com
Tue Mar 10 18:58:20 CET 2009
Reimar Döffinger wrote:
> On Tue, Mar 10, 2009 at 02:29:46PM +0300, Igor Katson wrote:
>> The problem is, that when I make a fifo, and send mplayer output to
>> -ao pcm:file=fifo,
>> and start encoding with oggenc, oggenc looks at the header
>> and thinks that the file is only 1 hour length, though it is much more,
>> and when an hour is encoded, oggenc just stops the process.
> Well, the problem is that it is not possible to put more than one hour
> of uncompressed data into wav, since wav specifies the size of the
> data as 32 bit values (due to broken sign handling actually 31 bit).
> One hour of data is already ca. 2 GB, and thus the limit for wav is
> reached (not sure if there are ODML extensions for wav, but even then I
> doubt oggenc would support them).
> Now as to why FFmpeg works: It just sets all those size values to 0 at
> the start, and oggenc obviously has special hacks to ignore that (if it
> behaved "correctly" oggenc would not encode a single byte with FFmpeg).
Just noticed that the SVN version of vorbis-tools has a special option
for this case:
--ignorelength Ignore the datalength in Wave headers. This allows
support for files > 4GB and STDIN data streams.
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