On 31/12/2020 13:36, Nicolas George wrote: > This mail is about a project I have to make FFmpeg's API and > infrastructure more convenient. For a common introduction, see this thread: > https://ffmpeg.org/pipermail/ffmpeg-devel/2020-December/274167.html > > The way we currently report errors is fine for command-line tools running in > a terminal, but it does not suit GUI applications at all: they will get a > generic error, translated into a vague string like "invalid argument", while > a more precise error message that tells which argument is invalid and how > will go to the log, and disappear in a black-hole like ~/.xsession-errors or > even /dev/null; at best, the application will have registered a log callback > and display the whole log to the user. > > I want to add a new API to return an error all at once, something like this: > > if (... failure condition...) > return av_error_set(ctx, AVERROR_INVALIDDATA, > "Syntax error in file ${file} line ${line}", > "file", finename, > "line", av_d2str(line), > NULL); > > The complete error message will be stored into a pre-allocated AVErrorStatus > structure in the context, and can be then retrieved by the application > using: > > av_error_get(ctx, buf); > > and displayed to the user in any convenient way (dialog box, HTTP response, > etc.). > > For compatibility, av_log(ctx, ...) will not only print to stderr, but also > keep the last line(s) of log in the AVErrorStatus buffer in ctx, so that > code that still does the good old: > > av_log(ctx, AV_LOG_ERROR, "Syntax error in file %s line %d\n", > filename, line); > return AVERROR_INVALIDDATA; > > will now work ok with av_error_get().
Finally having proper error support would be very nice; I like this idea a lot. What I'm a little iffy on is this last part, mostly because a lot of code in FFmpeg just returns an error without any av_log call, so the current error buffer in the context will at best be unrelated, or at worst, really misleading to the user. Cheers, - Derek _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
