From 7659712749500d2307c24abb188766f8a96d87be Mon Sep 17 00:00:00 2001 From: John Van Sickle Date: Wed, 6 Jan 2010 13:49:31 +0000 Subject: [PATCH] Fix entry on concatenating multiple yuv4mpegpipe streams. patch by John Van Sickle, john.vansickle gmail com Originally committed as revision 21033 to svn://svn.ffmpeg.org/ffmpeg/trunk --- doc/faq.texi | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/doc/faq.texi b/doc/faq.texi index 97fa3931cd..cf86616f9e 100644 --- a/doc/faq.texi +++ b/doc/faq.texi @@ -316,6 +316,11 @@ ffmpeg -f mpeg -i - -sameq -vcodec mpeg4 -acodec libmp3lame output.avi Similarly, the yuv4mpegpipe format, and the raw video, raw audio codecs also allow concatenation, and the transcoding step is almost lossless. +When using multiple yuv4mpegpipe(s), the first line needs to be discarded +from all but the first stream. This can be accomplished by piping through +@code{tail} as seen below. Note that when piping through @code{tail} you +must use command grouping, @code{@{ ;@}}, to background properly. + For example, let's say we want to join two FLV files into an output.flv file: @@ -329,7 +334,7 @@ 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 - > temp2.v < /dev/null & +@{ ffmpeg -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 \