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audiohook.c: resolving the issue with audiohook both reading when packet loss on one side of the call

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When there is 0% packet loss on one side of the call and 15% packet loss on the other side, reading frame is often failed when reading direction_both audiohook. when read_factory available = 0, write_factory available = 320; i think write factory is usable read; because after reading one frame, there is still another frame that can be read together with the next read factory frame.

Resolves: #851
(cherry picked from commit 23061fcaf7)
This commit is contained in:
Tinet-mucw
2024-08-22 14:42:19 +08:00
committed by Asterisk Development Team
parent 2566f41889
commit fc5a6e3bb3
1 changed files with 32 additions and 4 deletions
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36
main/audiohook.c
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@@ -280,14 +280,42 @@ static struct ast_frame *audiohook_read_frame_both(struct ast_audiohook *audioho
return NULL;
}
/* If we want to provide only a read factory make sure we aren't waiting for other audio */
if (usable_read && !usable_write && (ast_tvdiff_ms(ast_tvnow(), audiohook->write_time) < (samples/8)*2)) {
/* usable_read=1: indicates that read factory have the required samples
* usable_write=0: indicates that write factory have not the required samples
* usable_write, follows:
* 1. Due to RTT issues, the direction write frame has not been received,
* and it may take more than (samples/8)*2ms to receive it.
* 2. Due to packet loss, the direction write frame could not been received.
*
* (ast_tvdiff_ms(ast_tvnow(), audiohook->write_time) < (samples/8)*2)(Expression A): This ensures that
* packets on both sides can be read correctly even with RTT; however, if the RTT exceeds
* (samples/8)*2ms, it may result in the number of packets reading on both sides being greater than the
* actual number of packets. for example, this may cause the recording length of mixmonitor to be greater
* than the actual duration. Additionally, when RTT = 0 and packet loss is 50%, some packets in the
* write direction will never arrive. In this case, continuously waiting will only cause the read
* factory to exceed the safe length limit, resulting in both the read factory and write factory
* being cleared, thus same packets received in the read direction cannot be read.
*
* (ast_slinfactory_available(&audiohook->read_factory) < 2 * samples)(Expression B): This ensures that
* packets on both sides can be read correctly, even in the presence of packet loss; regardless of
* the amount of packet loss.
*
* (Expression A)&&(Expression B): This combination can comprehensively solve both RTT and packet loss
* issues; however when RTT exceeds (samples/8)*2ms, it may result in the number of packets read
* on both sides being greater than the actual number of packets, causing the recording length of
* mixmonitor to be longer than the actual duration. We can adjust (ast_tvdiff_ms(ast_tvnow(),
* audiohook->write_time)<(samples/8)*2) && (ast_slinfactory_available(&audiohook->read_factory) <
* 2 * samples) according to actual needs, for example, setting it to (ast_tvdiff_ms(ast_tvnow(),
* audiohook->write_time) < (samples/8)*4) && (ast_slinfactory_available(&audiohook->read_factory)
* < 4 * samples).
*/
if (usable_read && !usable_write && (ast_tvdiff_ms(ast_tvnow(), audiohook->write_time) < (samples/8)*2) && (ast_slinfactory_available(&audiohook->read_factory) < 2 * samples)) {
ast_debug(3, "Write factory %p was pretty quick last time, waiting for them.\n", &audiohook->write_factory);
return NULL;
}
/* If we want to provide only a write factory make sure we aren't waiting for other audio */
if (usable_write && !usable_read && (ast_tvdiff_ms(ast_tvnow(), audiohook->read_time) < (samples/8)*2)) {
/* As shown in the above comment. */
if (usable_write && !usable_read && (ast_tvdiff_ms(ast_tvnow(), audiohook->read_time) < (samples/8)*2) && (ast_slinfactory_available(&audiohook->write_factory) < 2 * samples)) {
ast_debug(3, "Read factory %p was pretty quick last time, waiting for them.\n", &audiohook->read_factory);
return NULL;
}