start time is out mp4

[Richard Kearsley]

Hi
I’m using the mp4 module quite heavily, and very occasionally (once 
every minute or so on a busy website) there is an error written to 
error.log and status 500 returned in the access log

[error] 42078#0: *5510811 start time is out mp4 stts samples in ... 
(mostly this error)
[error] 42072#0: *5524976 start time is out mp4 stsc chunks in ... 
(sometimes this error)

It happens on different videos and only when ?start is after a certain 
time point (different for each video)

Given that the mp4 module works remarkably well on the whole, where 
should I look to find the cause of these rare errors? (and what do they 
actually mean :))

nginx version: nginx/1.2.9
built by gcc 4.2.1 20070831 patched [FreeBSD]
TLS SNI support enabled
configure arguments: --with-debug --with-http_ssl_module 
--with-http_stub_status_module --with-file-aio --with-http_flv_module 
--with-http_mp4_module --with-http_geoip_module 
--add-module=../../../lua-nginx-module

Many thanks