[FFmpeg-user] Screencast produces only gray output

look at ebookring.net look at ebookring.net
Mon Nov 19 13:58:15 CET 2012


On 2012-11-19 05:09, Carl Eugen Hoyos wrote:
> <look <at> ebookring.net> writes:
>
>> ffmpeg -f alsa -ac 2 -i pulse -f x11grab -r 20 -s 1280x800
>> -i :0.0 -acodec pcm_s16le -vcodec libx264 -preset ultrafast
>> -crf 0 -threads 0 output.mkv
>
> If you don't want us to guess, please provide complete,
> uncut console output.
>
> If you'd like a guess, add -pix_fmt yuv420p.
> (Your original output file plays fine, your playback
> application is buggy / misses features.)
>
> Carl Eugen
>

Here's the output from Terminal using my original code;

$ ffmpeg -f alsa -ac 2 -i pulse -f x11grab -r 10 -s 1280x800 -i :0.0 
-acodec pcm_s16le -vcodec libx264 -pix_fmt yuv420p -preset ultrafast 
-crf 0 -threads 0 output.mkv
ffmpeg version N-42139-g7693543 Copyright (c) 2000-2012 the FFmpeg 
developers
   built on Nov  8 2012 22:15:12 with gcc 4.4.3 (Ubuntu 
4.4.3-4ubuntu5.1)
   configuration: --enable-gpl --enable-libfaac --enable-libmp3lame 
--enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libtheora 
--enable-libvorbis --enable-libvpx --enable-libx264 --enable-nonfree 
--enable-version3 --enable-x11grab
   libavutil      52.  5.100 / 52.  5.100
   libavcodec     54. 71.100 / 54. 71.100
   libavformat    54. 36.100 / 54. 36.100
   libavdevice    54.  3.100 / 54.  3.100
   libavfilter     3. 21.106 /  3. 21.106
   libswscale      2.  1.102 /  2.  1.102
   libswresample   0. 16.100 /  0. 16.100
   libpostproc    52.  1.100 / 52.  1.100
[alsa @ 0x9984580] Estimating duration from bitrate, this may be 
inaccurate
Guessed Channel Layout for  Input Stream #0.0 : stereo
Input #0, alsa, from 'pulse':
   Duration: N/A, start: 1353329751.457148, bitrate: 1536 kb/s
     Stream #0:0: Audio: pcm_s16le, 48000 Hz, stereo, s16, 1536 kb/s
[x11grab @ 0x9981bc0] device: :0.0 -> display: :0.0 x: 0 y: 0 width: 
1280 height: 800
[x11grab @ 0x9981bc0] shared memory extension found
[x11grab @ 0x9981bc0] Estimating duration from bitrate, this may be 
inaccurate
Input #1, x11grab, from ':0.0':
   Duration: N/A, start: 1353329751.563991, bitrate: 327680 kb/s
     Stream #1:0: Video: rawvideo (BGR[0] / 0x524742), bgr0, 1280x800, 
327680 kb/s, 10 tbr, 1000k tbn, 10 tbc
File 'output.mkv' already exists. Overwrite ? [y/N] y
using cpu capabilities: MMX2 SSE2Slow SlowCTZ
[libx264 @ 0x997c820] profile High 4:4:4 Predictive, level 3.2, 4:2:0 
8-bit
[libx264 @ 0x997c820] 264 - core 129 r16 1cffe9f - H.264/MPEG-4 AVC 
codec - Copyleft 2003-2012 - http://www.videolan.org/x264.html - 
options: cabac=0 ref=1 deblock=0:0:0 analyse=0:0 me=dia subme=0 psy=0 
mixed_ref=0 me_range=16 chroma_me=1 trellis=0 8x8dct=0 cqm=0 
deadzone=21,11 fast_pskip=0 chroma_qp_offset=0 threads=1 
lookahead_threads=1 sliced_threads=0 nr=0 decimate=1 interlaced=0 
bluray_compat=0 constrained_intra=0 bframes=0 weightp=0 keyint=250 
keyint_min=10 scenecut=0 intra_refresh=0 rc=cqp mbtree=0 qp=0
Output #0, matroska, to 'output.mkv':
   Metadata:
     encoder         : Lavf54.36.100
     Stream #0:0: Video: h264, yuv420p, 1280x800, q=-1--1, 1k tbn, 10 
tbc
     Stream #0:1: Audio: pcm_s16le, 48000 Hz, stereo, s16, 1536 kb/s
Stream mapping:
   Stream #1:0 -> #0:0 (rawvideo -> libx264)
   Stream #0:0 -> #0:1 (pcm_s16le -> pcm_s16le)
Press [q] to stop, [?] for help
frame=  230 fps=7.1 q=0.0 Lsize=   10363kB time=00:00:23.00 
bitrate=3691.0kbits/s
video:5988kB audio:4256kB subtitle:0 global headers:0kB muxing overhead 
1.158857%
[libx264 @ 0x997c820] frame I:1     Avg QP: 0.00  size:325928
[libx264 @ 0x997c820] frame P:229   Avg QP: 0.00  size: 25349
[libx264 @ 0x997c820] mb I  I16..4: 100.0%  0.0%  0.0%
[libx264 @ 0x997c820] mb P  I16..4:  2.2%  0.0%  0.0%  P16..4:  5.7%  
0.0%  0.0%  0.0%  0.0%    skip:92.0%
[libx264 @ 0x997c820] coded y,uvDC,uvAC intra: 69.3% 69.3% 69.1% inter: 
4.1% 5.5% 5.5%
[libx264 @ 0x997c820] i16 v,h,dc,p: 55% 45%  0%  0%
[libx264 @ 0x997c820] i8c dc,h,v,p: 35% 32% 31%  2%
[libx264 @ 0x997c820] kb/s:2132.51





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