I have found a bug in the software demultiplexer of the DVB driver.
The input buffer is passed by reference to the dvb_dmx_swfilter_section_feed function.
This function clears a part of the buffer, with the statement :
memset(buf, 0, DVB_DEMUX_MASK_MAX);
regardless of the size of the section.
As a result, when a section is shorter than DVB_DEMUX_MASK_MAX, the data of the next section are cleared.
This is an example :
before dvb_dmx_swfilter_section_feed:
70 70 05 CF 49 16 22 18 73 70 1A CF 49 16 22 18 F0 0F 58 0D 49 54 41 02 01 00 CE CA 01 00 00 01 00 9D 11 03 33 FF FF FF FF FF FF FF FF FF FF FF
after dvb_dmx_swfilter_section_feed:
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 58 0D 49 54 41 02 01 00 CE CA 01 00 00 01 00 9D 11 03 33 FF FF FF FF FF FF FF FF FF FF FF
I don't know exactly why it is necessary to clear the buffer, but if it is, I suggest the following patch :
--- dvb_demux.c.orig 2004-03-01 17:42:28.000000000 +0100 +++ dvb_demux.c 2004-03-01 17:43:42.000000000 +0100 @@ -213,10 +213,13 @@ return -1; } while ((f = f->next) && sec->is_filtering);
+ if (sec->seclen < DVB_DEMUX_MASK_MAX)
+ memset(buf, 0, sec->seclen);
+ else
+ memset(buf, 0, DVB_DEMUX_MASK_MAX);
+
sec->seclen = 0;- memset(buf, 0, DVB_DEMUX_MASK_MAX);
-
return 0;
}With this patch applied, the next section is no longer overwritten :
before dvb_dmx_swfilter_section_feed:
70 70 05 CF 49 16 32 23 73 70 1A CF 49 16 32 23 F0 0F 58 0D 49 54 41 02 01 00 CE CA 01 00 00 01 00 F3 64 BB C7 FF FF FF FF FF FF FF FF FF FF FF
after dvb_dmx_swfilter_section_feed:
00 00 00 00 00 00 00 00 73 70 1A CF 49 16 32 23 F0 0F 58 0D 49 54 41 02 01 00 CE CA 01 00 00 01 00 F3 64 BB C7 FF FF FF FF FF FF FF FF FF FF FF
That patch solves the problem found by Uberto Barbini last week.
Jean-Claude
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