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-rw-r--r-- | doc/faq.texi | 72 |
1 files changed, 33 insertions, 39 deletions
diff --git a/doc/faq.texi b/doc/faq.texi index 91a380e573..f3ddbbe811 100644 --- a/doc/faq.texi +++ b/doc/faq.texi @@ -24,10 +24,10 @@ No. Windows DLLs are not portable, bloated and often slow. Moreover Libav strives to support all codecs natively. A DLL loader is not conducive to that goal. -@section I cannot read this file although this format seems to be supported by ffmpeg. +@section I cannot read this file although this format seems to be supported by avconv. -Even if ffmpeg can read the container format, it may not support all its -codecs. Please consult the supported codec list in the ffmpeg +Even if avconv can read the container format, it may not support all its +codecs. Please consult the supported codec list in the avconv documentation. @section Which codecs are supported by Windows? @@ -81,12 +81,6 @@ problem and an NP-hard problem... @chapter Usage -@section ffmpeg does not work; what is wrong? - -Try a @code{make distclean} in the ffmpeg source directory before the build. -If this does not help see our -@uref{http://libav.org/bugreports.html, bug reporting guidelines}. - @section How do I encode single pictures into movies? First, rename your pictures to follow a numerical sequence. @@ -94,7 +88,7 @@ For example, img1.jpg, img2.jpg, img3.jpg,... Then you may run: @example - ffmpeg -f image2 -i img%d.jpg /tmp/a.mpg + avconv -f image2 -i img%d.jpg /tmp/a.mpg @end example Notice that @samp{%d} is replaced by the image number. @@ -117,17 +111,17 @@ If you want to sequence them by oldest modified first, substitute Then run: @example - ffmpeg -f image2 -i /tmp/img%03d.jpg /tmp/a.mpg + avconv -f image2 -i /tmp/img%03d.jpg /tmp/a.mpg @end example -The same logic is used for any image format that ffmpeg reads. +The same logic is used for any image format that avconv reads. @section How do I encode movie to single pictures? Use: @example - ffmpeg -i movie.mpg movie%d.jpg + avconv -i movie.mpg movie%d.jpg @end example The @file{movie.mpg} used as input will be converted to @@ -135,15 +129,15 @@ The @file{movie.mpg} used as input will be converted to Instead of relying on file format self-recognition, you may also use @table @option -@item -vcodec ppm -@item -vcodec png -@item -vcodec mjpeg +@item -c:v ppm +@item -c:v png +@item -c:v mjpeg @end table to force the encoding. Applying that to the previous example: @example - ffmpeg -i movie.mpg -f image2 -vcodec mjpeg menu%d.jpg + avconv -i movie.mpg -f image2 -c:v mjpeg menu%d.jpg @end example Beware that there is no "jpeg" codec. Use "mjpeg" instead. @@ -165,13 +159,13 @@ Try '-f image2 test%d.jpg'. @section Why can I not change the framerate? Some codecs, like MPEG-1/2, only allow a small number of fixed framerates. -Choose a different codec with the -vcodec command line option. +Choose a different codec with the -c:v command line option. -@section How do I encode Xvid or DivX video with ffmpeg? +@section How do I encode Xvid or DivX video with avconv? Both Xvid and DivX (version 4+) are implementations of the ISO MPEG-4 standard (note that there are many other coding formats that use this -same standard). Thus, use '-vcodec mpeg4' to encode in these formats. The +same standard). Thus, use '-c:v mpeg4' to encode in these formats. The default fourcc stored in an MPEG-4-coded file will be 'FMP4'. If you want a different fourcc, use the '-vtag' option. E.g., '-vtag xvid' will force the fourcc 'xvid' to be stored as the video fourcc rather than the @@ -188,7 +182,7 @@ things to try: '-bf 2', '-flags qprd', '-flags mv0', '-flags skiprd'. but beware the '-g 100' might cause problems with some decoders. Things to try: '-bf 2', '-flags qprd', '-flags mv0', '-flags skiprd. -@section Interlaced video looks very bad when encoded with ffmpeg, what is wrong? +@section Interlaced video looks very bad when encoded with avconv, what is wrong? You should use '-flags +ilme+ildct' and maybe '-flags +alt' for interlaced material, and try '-top 0/1' if the result looks really messed-up. @@ -203,9 +197,9 @@ Just create an "input.avs" text file with this single line ... @example DirectShowSource("C:\path to your file\yourfile.asf") @end example -... and then feed that text file to ffmpeg: +... and then feed that text file to avconv: @example - ffmpeg -i input.avs + avconv -i input.avs @end example For ANY other help on Avisynth, please visit the @@ -222,13 +216,13 @@ equally humble @code{copy} under Windows), and finally transcoding back to your format of choice. @example -ffmpeg -i input1.avi -sameq intermediate1.mpg -ffmpeg -i input2.avi -sameq intermediate2.mpg +avconv -i input1.avi -same_quant intermediate1.mpg +avconv -i input2.avi -same_quant intermediate2.mpg cat intermediate1.mpg intermediate2.mpg > intermediate_all.mpg -ffmpeg -i intermediate_all.mpg -sameq output.avi +avconv -i intermediate_all.mpg -same_quant output.avi @end example -Notice that you should either use @code{-sameq} or set a reasonably high +Notice that you should either use @code{-same_quant} or set a reasonably high bitrate for your intermediate and output files, if you want to preserve video quality. @@ -238,10 +232,10 @@ of named pipes, should your platform support it: @example mkfifo intermediate1.mpg mkfifo intermediate2.mpg -ffmpeg -i input1.avi -sameq -y intermediate1.mpg < /dev/null & -ffmpeg -i input2.avi -sameq -y intermediate2.mpg < /dev/null & +avconv -i input1.avi -same_quant -y intermediate1.mpg < /dev/null & +avconv -i input2.avi -same_quant -y intermediate2.mpg < /dev/null & cat intermediate1.mpg intermediate2.mpg |\ -ffmpeg -f mpeg -i - -sameq -vcodec mpeg4 -acodec libmp3lame output.avi +avconv -f mpeg -i - -same_quant -c:v mpeg4 -acodec libmp3lame output.avi @end example Similarly, the yuv4mpegpipe format, and the raw video, raw audio codecs also @@ -260,15 +254,15 @@ mkfifo temp2.a mkfifo temp2.v mkfifo all.a mkfifo all.v -ffmpeg -i input1.flv -vn -f u16le -acodec pcm_s16le -ac 2 -ar 44100 - > temp1.a < /dev/null & -ffmpeg -i input2.flv -vn -f u16le -acodec pcm_s16le -ac 2 -ar 44100 - > temp2.a < /dev/null & -ffmpeg -i input1.flv -an -f yuv4mpegpipe - > temp1.v < /dev/null & -@{ ffmpeg -i input2.flv -an -f yuv4mpegpipe - < /dev/null | tail -n +2 > temp2.v ; @} & +avconv -i input1.flv -vn -f u16le -acodec pcm_s16le -ac 2 -ar 44100 - > temp1.a < /dev/null & +avconv -i input2.flv -vn -f u16le -acodec pcm_s16le -ac 2 -ar 44100 - > temp2.a < /dev/null & +avconv -i input1.flv -an -f yuv4mpegpipe - > temp1.v < /dev/null & +@{ avconv -i input2.flv -an -f yuv4mpegpipe - < /dev/null | tail -n +2 > temp2.v ; @} & cat temp1.a temp2.a > all.a & cat temp1.v temp2.v > all.v & -ffmpeg -f u16le -acodec pcm_s16le -ac 2 -ar 44100 -i all.a \ +avconv -f u16le -acodec pcm_s16le -ac 2 -ar 44100 -i all.a \ -f yuv4mpegpipe -i all.v \ - -sameq -y output.flv + -same_quant -y output.flv rm temp[12].[av] all.[av] @end example @@ -304,7 +298,7 @@ the silver bullet that solves this problem, feel free to shoot it at us. We strongly recommend you to move over from MSVC++ to MinGW tools. -@section Can I use Libav or libavcodec under Windows? +@section Can I use Libav under Windows? Yes, but the Cygwin or MinGW tools @emph{must} be used to compile Libav. Read the @emph{Windows} section in the Libav documentation to find more @@ -314,7 +308,7 @@ information. No. These tools are too bloated and they complicate the build. -@section Why not rewrite ffmpeg in object-oriented C++? +@section Why not rewrite Libav in object-oriented C++? Libav is already organized in a highly modular manner and does not need to be rewritten in a formal object language. Further, many of the developers @@ -327,7 +321,7 @@ Yes, as long as the code is optional and can easily and cleanly be placed under #if CONFIG_GPL without breaking anything. So for example a new codec or filter would be OK under GPL while a bug fix to LGPL code would not. -@section I'm using libavcodec from within my C++ application but the linker complains about missing symbols which seem to be available. +@section I'm using Libav from within my C++ application but the linker complains about missing symbols which seem to be available. Libav is a pure C project, so to use the libraries within your C++ application you need to explicitly state that you are using a C library. You can do this by |