On 26/02/17 12:10, Nicolas George wrote: > L'octidi 8 ventôse, an CCXXV, Mark Thompson a écrit : >> It at least offers some direction for where to go looking for the >> problem. > > None at all. > >> What form would you suggest the message takes? > > It depends. > >>> To get more relevant advice, I believe you need to explain, here and >>> now, what causes the error: user settings, system/hardware, or bug. >> Yes, I suppose it must be one of those. > > Of course it is one of those. The question is WHICH ONE?
I have no idea: that's why I'm adding this error code feedback so that there is more information available in the log to debug such problems if they occur. Even for documented error codes like "invalid video parameters" the answer is not clear: User settings: the requested combination of formats is not supported (fix by changing the filter parameters). System: the format is supported, but not in this version (fix by upgrading the library). Hardware: the format is supported, but not on this hardware (fix by using newer hardware). Bug: the wrong parameters were passed to the library (fix in Libav). Now, in theory all but the first of those should be possible to eliminate, but the effort required to do so is high and noone has yet done so. (And I believe they are unlikely to, given the niche use of this filter by a small number of users who are likely to be relatively clueful.) >> (The -16 (MFX_ERR_UNDEFINED_BEHAVIOUR) that I get is not documented as >> a valid return value from the function >> <https://software.intel.com/en-us/node/628434#MFXVideoVPP1>, so it is >> difficult to read anything into it.) > > For that, the correct error message would be "bug in the Quick Sync > library", telling the user there is nothing they can do to get it > working. The actual error code, if useful, does not belong in a message > at AV_LOG_ERROR message but at AV_LOG_DEBUG. But that isn't true. It is a bug in the documentation, yes, but that doesn't mean there isn't some way to make it work involving doing something different with the input surfaces (for the case here the user certainly knows that they did something interesting to get to this situation, since they must have set up the surfaces themselves or used the hwmap filter). _______________________________________________ libav-devel mailing list [email protected] https://lists.libav.org/mailman/listinfo/libav-devel
