[MPlayer-dev-eng] Re: Another ATSC "a52: CRC check failed" problem

mplayer mplayer.rm at muth.org
Sun Feb 26 18:38:47 CET 2006


Hi:

I am a Time warner customer in  New York using the  HD-3000 atsc card.
On almost all channels I had  a lot of failures, like

a52: CRC check failed!   -0.033 ct: -1.211 369/369 10% 15%  0.7% 0 
0                           
a52: error at resampling

Then came Nico's patch:

 >Nico Sabbi wrote://
 >
 >patch attached.
 >Having a largish tsprobe value helps.
 >
 >Please, let me know if this patch helps you.

I applied this patch and this has reduced the number of failures
dramatically.
There are still a few a52 error and occasionally they cause the player 
to abort
(usually the player has trouble synchonzing sound and video and then 
gives up).

I have a number of questions:

1) Can I make mplayer a little bit more tolerant to a52 errors, so that 
it does
   give up so easily or goes into some weird synchronization mode where
   either video or audio stops.
2) As Trent pointed out below, not all crc errors are related to the
    demux_ts code. Is there a place in the a52 code where I could add a 
print statement
    to  see whether a crc  error is worth reporting to Nico or not. E.g. 
apparently I not should
    not report short AC3 frame
3) If I find "report worthy" crc errors, how do a capture a ts stream 
that will allow you to look at
    the problem. (sorry I am a bit new to the atsc stuff)

Thanks,

    Robert

/> Trent Piepho wrote:
/>There is just one CRC error in that ts capture, but it is an AC3 frame 
which
i>s short 184 bytes. Obviously one TS packet was dropped and it probably has
 >nothing to do with mplayer, or at least is a totaly different problem.




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