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added proper waiting (up to 10ms) for the DAHDI transcoder output frame 

git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@13262 d0543943-73ff-0310-b7d9-9358b9ac24b2
This commit is contained in:
Moises Silva 2009-05-08 04:40:32 +00:00
parent 4c80273fbf
commit 770a1e522b
1 changed files with 16 additions and 3 deletions
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19
src/mod/codecs/mod_dahdi_codec/mod_dahdi_codec.c
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@ -39,6 +39,16 @@
#include <fcntl.h>
#include <errno.h>
/*
* some rules to keep in mind for G729 (the frame size may be different for G723)
* we cannot write more than SFRAME_SIZE (320) - sizeof(struct rtp_packet) which
* seems to be 266 bytes
* if we write less than 160 bytes (1 ulaw frame which is 20 bytes of G729 bytes, a read will block forever)
* TODO: do buffering ourselves to provide just the fixed amount of samples that the card expects
* */
#define DAHDI_G729_INPUT_FRAME_SIZE 160
#define DAHDI_G729_OUTPUT_FRAME_SIZE 20
/*#define DEBUG_DAHDI_CODEC 1*/
#define CODEC_G729_IANA_CODE 18
@ -221,19 +231,22 @@ static switch_status_t switch_dahdi_init(switch_codec_t *codec, switch_codec_fla
context->codec_r = (codec->implementation->ianacode == CODEC_G729_IANA_CODE)
? 8 : 12;
return SWITCH_STATUS_SUCCESS;
}
static int wait_for_transcoder(int fd)
{
/* let's wait a bit for the transcoder, if in 20msthe driver does not notify us that its ready to accept more works
/* let's wait a bit for the transcoder, if in 20msthe driver does not notify us that its ready to give us something
then just bail out with 0 bytes encoded/decoded as result, I'd expect the card to hold that buffer and return it later */
int res = 0;
struct pollfd readpoll;
memset(&readpoll, 0, sizeof(readpoll));
readpoll.fd = fd;
readpoll.events = POLLOUT;
res = poll(&readpoll, 1, 50);
readpoll.events = POLLIN;
/* my testing shows that it does not take more than 1ms to encode a 160 bytes frame ulaw to g729,
I dont think there is much difference decoding and for g723, waiting 10ms seems more than reasonable */
res = poll(&readpoll, 1, 10);
return res;
}