Quoting Soft Works (2022-06-05 09:54:51) > > > > -----Original Message----- > > From: ffmpeg-devel <ffmpeg-devel-boun...@ffmpeg.org> On Behalf Of Anton > > Khirnov > > Sent: Sunday, June 5, 2022 9:01 AM > > To: FFmpeg development discussions and patches <ffmpeg-devel@ffmpeg.org> > > Subject: Re: [FFmpeg-devel] [PATCH 1/8] lavc/avcodec: simplify codec id/type > > validity checking > > > > Quoting Soft Works (2022-06-05 07:23:18) > > > This is causing a regression in ffprobe. > > > > > > The commit removes the special-case check for AVMEDIA_TYPE_ATTACHMENT > > > which > > > was required for ffprobe and had been added with > > e83c716e16c52fa56a78274408f7628e5dc719da. > > > > > > The demand from the commit message is not yet guaranteed to be fulfilled: > > > > > > > On entry to avcodec_open2(), the type and id either have to be > > > > UNKNOWN/NONE or have to match the codec to be used. > > > > > > I have one verified example (maybe a second will follow), which is an MKV > > with > > > an attachment "stream" of type "text". > > > The found codec will be textdec of type 'subtitle' even though the stream > > type > > > is attachment. Without the special condition for attachment streams, this > > > is now causing ffprobe to error out with non-zero exit code and incomplete > > > output. > > > > > > > > > ------------------------------------------------------------------------ > > > Example: > > > > > > [...] > > > Stream #0:9: Attachment: text > > > Metadata: > > > filename : textfile.text > > > mimetype : text/plain > > > [text @ 000001AC32310340] Codec type or id mismatches > > > Could not open codec for input stream 9 > > > ------------------------------------------------------------------------ > > > > This sounds very much like a bug in ffprobe. It makes no sense to call > > avcodec_open2() with the AVMEDIA_TYPE_ATTACHMENT type. > > You make a behavioral change to an API function that had this behavior > established and constant over more than 10 years, and when that change > breaks functionality, it's the callers' fault? > How does this go together with all that peanut counting of major, minor > and micro version numbers per library? What is this versioning good for, > when you can make breaking changes and declare the breakage as bugs?
We maintain compatibility for valid API usage. We do not maintain bug compatibility. I fail to see how calling avcodec_open2() with AVMEDIA_TYPE_ATTACHMENT is valid API usage. What do you expect it to do? There are no AVMEDIA_TYPE_ATTACHMENT decoders. More generally, arguments along the line of "change <X> is needed to keep program <Y> working>" on their own sound very shady to me and suggest that perhaps program <Y> should not be doing whatever it is doing. -- Anton Khirnov _______________________________________________ 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".
