eval: Add taylor series evaluation support.

[ffmpeg] / doc / faq.texi

diff --git a/doc/faq.texi b/doc/faq.texi
index 3ad503dc834a2791662c478bffe8c3a6fec6c203..5f371a45463ebe7a834657506e222ec8c208cb64 100644 (file)
--- a/doc/faq.texi
+++ b/doc/faq.texi
@@ -272,6 +272,44 @@ ffmpeg -f u16le -acodec pcm_s16le -ac 2 -ar 44100 -i all.a \
 rm temp[12].[av] all.[av]
 @end example
 
+@section -profile option fails when encoding H.264 video with AAC audio
+
+@command{ffmpeg} prints an error like
+
+@example
+Undefined constant or missing '(' in 'baseline'
+Unable to parse option value "baseline"
+Error setting option profile to value baseline.
+@end example
+
+Short answer: write @option{-profile:v} instead of @option{-profile}.
+
+Long answer: this happens because the @option{-profile} option can apply to both
+video and audio.  Specifically the AAC encoder also defines some profiles, none
+of which are named @var{baseline}.
+
+The solution is to apply the @option{-profile} option to the video stream only
+by using @url{http://ffmpeg.org/ffmpeg.html#Stream-specifiers-1, Stream specifiers}.
+Appending @code{:v} to it will do exactly that.
+
+@section Using @option{-f lavfi}, audio becomes mono for no apparent reason.
+
+Use @option{-dumpgraph -} to find out exactly where the channel layout is
+lost.
+
+Most likely, it is through @code{auto-inserted aconvert}. Try to understand
+why the converting filter was needed at that place.
+
+Just before the output is a likely place, as @option{-f lavfi} currently
+only support packed S16.
+
+Then insert the correct @code{aconvert} explicitly in the filter graph,
+specifying the exact format.
+
+@example
+aconvert=s16:stereo:packed
+@end example
+
 @chapter Development
 
 @section Are there examples illustrating how to use the FFmpeg libraries, particularly libavcodec and libavformat?
@@ -377,4 +415,16 @@ wrong if it is larger than the average!
 For example, if you have mixed 25 and 30 fps content, then r_frame_rate
 will be 150.
 
+@section Why is @code{make fate} not running all tests?
+
+Make sure you have the fate-suite samples and the @code{SAMPLES} Make variable
+or @code{FATE_SAMPLES} environment variable or the @code{--samples}
+@command{configure} option is set to the right path.
+
+@section Why is @code{make fate} not finding the samples?
+
+Do you happen to have a @code{~} character in the samples path to indicate a
+home directory? The value is used in ways where the shell cannot expand it,
+causing FATE to not find files. Just replace @code{~} by the full path.
+
 @bye