# wowza zero typed function error, ffmpeg error warnin QUEUE INPUT IS BACKWARD IN TIME **URL:** \ **Category:** Wowza Streaming Engine\ **Created:** [September 22, 2015, 2:58am UTC](https://community.wowza.com/t/wowza-zero-typed-function-error-ffmpeg-error-warnin-queue-input-is-backward-in-time/45121 "2015-09-22T02:58:55Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![todafuture\_todafutur](https://avatars.discourse-cdn.com/v4/letter/t/ea666f/32.png) [@todafuture\_todafutur](https://community.wowza.com/u/todafuture_todafutur)\ **Post date:** [September 22, 2015, 2:58am UTC](https://community.wowza.com/t/wowza-zero-typed-function-error-ffmpeg-error-warnin-queue-input-is-backward-in-time/45121/1 "2015-09-22T02:58:55Z")
I uses this command of ffmpeg to publish stream to wowza : ffmpeg -threads 6 -rtbufsize 2000M -f dshow -video\_size 1920x1080 -i video=“7160 HD Capture”:audio=“7160 HD Capture” -acodec aac -ar 48000 -strict experimental -vcodec libx264 -x264opts keyint=25:min-keyint=20 -b:v 2048k -preset ultrafast -tune zerolatency -r 10 -pix\_fmt yuv420p -f flv rtmp://localhost:1935/live/test The video runs nicely and smoothly for about 10 min and stops but the ffmpeg process still keeps running (but in reality the streaming process does not work anymore) , I see the log of Wowza and it shows Zero sized function in wowza log, for ffmpeg it shows yellow warning QUEUE INPUT IS BACKWARD IN TIME (ffmpeg still was running but no streaming process was available to play on wowza). Searching on Internet they say ‘zero sized function’ error is something with long pause, I tried to modified setenv.sh in several ways according to the performance tuning wowza page, but that still does not solve the problem. Do you know how to solve this QUEUE INPUT IS BACKWARD IN TIME and ZERO SIZED FUNCTION? Thank you very much. ---
**Author:** ![Paul\_Shields](https://sea2.discourse-cdn.com/flex002/user_avatar/community.wowza.com/paul_shields/32/390_2.png) [@Paul\_Shields](https://community.wowza.com/u/Paul_Shields)\ **Post date:** [September 23, 2015, 4:12pm UTC](https://community.wowza.com/t/wowza-zero-typed-function-error-ffmpeg-error-warnin-queue-input-is-backward-in-time/45121/2 "2015-09-23T16:12:15Z")
Hi, There are a number of reasons as to why you may see an error related to zero sized functions. Often it is related to lack of resources or memory. Please raise a [support ticket](https://www.wowza.com/support/open-ticket) providing the details as described in the article and reference this thread and we can take a closer look. Paul ---
**Author:** ![sal\_jefferson](https://avatars.discourse-cdn.com/v4/letter/s/6de8d8/32.png) [@sal\_jefferson](https://community.wowza.com/u/sal_jefferson)\ **Post date:** [October 6, 2015, 8:17am UTC](https://community.wowza.com/t/wowza-zero-typed-function-error-ffmpeg-error-warnin-queue-input-is-backward-in-time/45121/3 "2015-10-06T08:17:19Z")
Thanks for the update, and for posting the solution here for others. Regards, Salvadore ---
**Author:** ![Paul\_Shields](https://sea2.discourse-cdn.com/flex002/user_avatar/community.wowza.com/paul_shields/32/390_2.png) [@Paul\_Shields](https://community.wowza.com/u/Paul_Shields)\ **Post date:** [September 25, 2015, 11:26am UTC](https://community.wowza.com/t/wowza-zero-typed-function-error-ffmpeg-error-warnin-queue-input-is-backward-in-time/45121/4 "2015-09-25T11:26:02Z")
Hi, Can you please provide the ticket reference number and we can further update you via that process. Regards, Paul ---
**Author:** ![Paul\_Shields](https://sea2.discourse-cdn.com/flex002/user_avatar/community.wowza.com/paul_shields/32/390_2.png) [@Paul\_Shields](https://community.wowza.com/u/Paul_Shields)\ **Post date:** [October 1, 2015, 5:25pm UTC](https://community.wowza.com/t/wowza-zero-typed-function-error-ffmpeg-error-warnin-queue-input-is-backward-in-time/45121/5 "2015-10-01T17:25:27Z")
Hi, It looks like this was resolved successfully in the ticket. Regards, Paul ---
**Author:** ![todafuture\_todafutur](https://avatars.discourse-cdn.com/v4/letter/t/ea666f/32.png) [@todafuture\_todafutur](https://community.wowza.com/u/todafuture_todafutur)\ **Post date:** [September 23, 2015, 5:56pm UTC](https://community.wowza.com/t/wowza-zero-typed-function-error-ffmpeg-error-warnin-queue-input-is-backward-in-time/45121/6 "2015-09-23T17:56:18Z")
The details of the article, logs, conf and setenv.sh files were sent to support@wowza.com . ---
**Author:** ![todafuture\_todafutur](https://avatars.discourse-cdn.com/v4/letter/t/ea666f/32.png) [@todafuture\_todafutur](https://community.wowza.com/u/todafuture_todafutur)\ **Post date:** [September 25, 2015, 12:04am UTC](https://community.wowza.com/t/wowza-zero-typed-function-error-ffmpeg-error-warnin-queue-input-is-backward-in-time/45121/7 "2015-09-25T00:04:52Z")
Any help for this Zero sized function? I search all the Internet and I find no solution for this error. All performance tuning changes I tried did not work. The logs in Wowza says only ‘Zero sized function’ with no other clues. The error Queue input is backward in time of ffmpeg (then ffmpeg still keeps running) probably occurred after Wowza streaming process had already stopped. ---
**Author:** ![todafuture\_todafutur](https://avatars.discourse-cdn.com/v4/letter/t/ea666f/32.png) [@todafuture\_todafutur](https://community.wowza.com/u/todafuture_todafutur)\ **Post date:** [September 25, 2015, 9:08pm UTC](https://community.wowza.com/t/wowza-zero-typed-function-error-ffmpeg-error-warnin-queue-input-is-backward-in-time/45121/8 "2015-09-25T21:08:19Z")
The ticket number is 142332. Thank you. ---
**Author:** ![todafuture\_todafutur](https://avatars.discourse-cdn.com/v4/letter/t/ea666f/32.png) [@todafuture\_todafutur](https://community.wowza.com/u/todafuture_todafutur)\ **Post date:** [October 3, 2015, 1:31am UTC](https://community.wowza.com/t/wowza-zero-typed-function-error-ffmpeg-error-warnin-queue-input-is-backward-in-time/45121/9 "2015-10-03T01:31:57Z")
Solution: This is because the network bandwidth where ffmpeg is run is limited. This leads to rtbufsize error and Wowza by default do not handle rtbufsize 2000M case --\> leads to Zero typed function. Solution is to Reduce -rtbufsize to 700M and use a good network (although it is possible, avoid playing video on the same machine to save bandwidth and avoid delays). This command solves the problem for the 7160 HD Capture card: ffmpeg -threads 6 -rtbufsize 700M -thread\_queue\_size 100 -f dshow -video\_size 1280x720 -i video=“7160 HD Capture”:audio=“7160 HD Capture” -i logo1.png -filter\_complex “[0:v][1:v] overlay=137:577” -vcodec libx264 -b:v 2048k -preset superfast -tune zerolatency -r 24 -acodec aac -ar 44100 -strict experimental -f flv - | ffmpeg -i - -acodec copy -vcodec copy -f flv rtmp://server:1935/live/test