[FFmpeg-devel] [PATCH] lavf/utils: extend has_codec_parameters() to make it show what info is missing

[Stefano Sabatini]

On date Tuesday 2012-07-17 17:00:44 +0200, Michael Niedermayer encoded:
> On Tue, Jul 17, 2012 at 09:04:47AM +0200, Stefano Sabatini wrote:
> > On date Monday 2012-07-16 05:04:55 +0200, Michael Niedermayer encoded:
> > > On Mon, Jul 16, 2012 at 12:30:58AM +0200, Stefano Sabatini wrote:
> > > > Improve feedback.
> > > > ---
> > > >  libavformat/utils.c |   47 ++++++++++++++++++++++++++++++-----------------
> > > >  1 files changed, 30 insertions(+), 17 deletions(-)
> > > > 
> > > > diff --git a/libavformat/utils.c b/libavformat/utils.c
> > > > index 39527a6..74b6746 100644
> > > > --- a/libavformat/utils.c
> > > > +++ b/libavformat/utils.c
> > > > @@ -2265,30 +2265,40 @@ static void estimate_timings(AVFormatContext *ic, int64_t old_offset)
> > > >      }
> > > >  }
> > > >  
> > > > -static int has_codec_parameters(AVStream *st)
> > > > +static int has_codec_parameters(AVStream *st, char *error, size_t error_size)
> > > >  {
> > > >      AVCodecContext *avctx = st->codec;
> > > > -    int val;
> > > > +
> > > > +#define FAIL(errmsg) do {                               \
> > > > +        if (error)                                      \
> > > > +            av_strlcpy(error, errmsg, error_size);      \
> > > > +        return 0;                                       \
> > > > +    } while (0)
> > > > +
> > > 
> > > passing a flag into has_codec_parameters() and printing the message
> > > in there when its != 0 seems cleaner
> > > not sure if theres a even cleaner way
> > 
> > The problem is that when the codec parameters are checked the codec is
> > not yet set, so you'll see a message of the kind:
> > 
> > [flv @ 0x3303160] max_analyze_duration 5000000 reached at 5018000
> > [NULL @ 0x33095c0] Unspecified frame size
> > [flv @ 0x3303160] Could not find codec parameters (Video: h264, 204 kb/s)
> > 
> > which is not very useful.
> 
> AVFormatContext could be passed into has_codec_parameters()

Nitfest.

Currently:
static int has_codec_parameters(AVStream *st)
=>
[flv @ 0x3303160] max_analyze_duration 5000000 reached at 5018000
[flv @ 0x3303160] Could not find codec parameters (Video: h264, 204 kb/s)

Alternative 1:
static int has_codec_parameters(AVStream *st, void *logctx)
=>
[flv @ 0x3303160] max_analyze_duration 5000000 reached at 5018000
[flv @ 0x3303160] Unspecified frame size for stream (Video: h264, 204 kb/s)
[flv @ 0x3303160] Could not find codec parameters for stream 0 (Video: h264, 204 kb/s)

Alternative 2:
static int has_codec_parameters(AVStream *st, char *msg, size_t msg_size)
=>
[flv @ 0x3303160] max_analyze_duration 5000000 reached at 5018000
[flv @ 0x3303160] Could not find codec parameters for stream 0 (Video: h264, 204 kb/s): unspecified frame size

With alternative 1 there is no way to show the stream index, since
has_codec_parameters() takes in input the stream, and the index may
not be available when the function is called (may be an issue if you
have several streams of the same type in input).

Alternative 2 provides the most useful and complete feedback IMHO, but
I'm fine with 1 if you dislike it very much.
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