[FFmpeg-devel] [PATCH]lavf/matroskaenc: Print an error if an unreadable rawvideo pix_fmt is written

[wm4]

On Thu, 12 Jan 2017 23:31:11 +0100
Carl Eugen Hoyos <ceffmpeg at gmail.com> wrote:

> 2017-01-12 23:20 GMT+01:00 Hendrik Leppkes <h.leppkes at gmail.com>:
> > On Fri, Jan 13, 2017 at 1:10 AM, Carl Eugen Hoyos <ceffmpeg at gmail.com> wrote:  
> >> 2017-01-11 12:24 GMT+01:00 Moritz Barsnick <barsnick at gmx.net>:  
> >>> On Tue, Jan 10, 2017 at 17:05:47 +0100, Carl Eugen Hoyos wrote:  
> >>>> +                enum AVPixelFormat pix_fmt = avpriv_find_pix_fmt(avpriv_pix_fmt_bps_avi,
> >>>> +                                                                 par->bits_per_coded_sample);
> >>>> +                if (par->format != pix_fmt && par->format != AV_PIX_FMT_NONE)
> >>>> +                    av_log(s, AV_LOG_ERROR, "%s rawvideo cannot be written to vfw mkv, output file will be unreadable\n",
> >>>> +                          av_get_pix_fmt_name(par->format));  
> >>>
> >>> Should it really be an error (and not a warning) if its detection
> >>> doesn't change ffmpeg's behavior?  
> >>
> >> Just copying what avi and mov muxer do.
> >>
> >> Note that (many) decoders print errors and (can) continue.
> >>
> >> (I believe library users can - and do - put rawvideo into standard
> >> containers and force the right pix_fmt on reading.)  
> >
> > That seems silly, we shouldn't log an error that a file will be broken
> > and then still write it. Muxers should be strict and write only valid
> > files.  
> 
> This is what we currently do for both other multi-purpose containers
> (while FFmpeg logs no message for unreadable transport streams),
> so lets please commit this.

I have to agree with Hendrik. Your patch is all about adding a message
for this case. Why not do the right thing in the first place? You'd
only have to add an error return or so.