[FFmpeg-user] ffmpeg ac-3 encoding speed

[Davor Josipovic]

On 2/09/2012 5:38, Roger Pack wrote:
>> ffmpeg -i %tmp_orig_audio% -c:a ac3 -ab 640k -q:a 0 %tmp_enc_audio%
>>
>> Now, on an Intel i3 machine using only one core, approximately 60sec of
>> this DTS stream is converted each second. It is almost as fast as the disk
>> can write and read.
>>
>> Is this encoding speed normal or am I doing something wrong?
>
> What's your full command line and uncut console output?
> -r
>

The command line is as noted in the original post with extra options:

	-y -analyzeduration 100M

The console output:

ffmpeg version N-40301-gc1fe2db Copyright (c) 2000-2012 the FFmpeg 
developers
   built on May  3 2012 11:42:19 with gcc 4.6.3
   configuration: --disable-static --enable-shared --enable-gpl 
--enable-version3
  --disable-w32threads --enable-runtime-cpudetect --enable-avisynth 
--enable-bzli
b --enable-frei0r --enable-libass --enable-libcelt 
--enable-libopencore-amrnb --
enable-libopencore-amrwb --enable-libfreetype --enable-libgsm 
--enable-libmp3lam
e --enable-libnut --enable-libopenjpeg --enable-librtmp 
--enable-libschroedinger
  --enable-libspeex --enable-libtheora --enable-libutvideo 
--enable-libvo-aacenc
--enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx 
--enable-libx264 --en
able-libxavs --enable-libxvid --enable-zlib
   libavutil      51. 49.100 / 51. 49.100
   libavcodec     54. 17.101 / 54. 17.101
   libavformat    54.  3.100 / 54.  3.100
   libavdevice    53.  4.100 / 53.  4.100
   libavfilter     2. 72.104 /  2. 72.104
   libswscale      2.  1.100 /  2.  1.100
   libswresample   0. 11.100 /  0. 11.100
   libpostproc    52.  0.100 / 52.  0.100
Input #0, matroska,webm, from 'W:\transcode\tmp\tmp_orig_audio.mkv':
   Metadata:
     title           : Test
     creation_time   : 2012-09-01 21:31:06
   Duration: 02:12:28.97, start: 0.000000, bitrate: 1506 kb/s
     Stream #0:0(eng): Audio: dts (DTS), 48000 Hz, 5.1(side), s16, 1536 
kb/s (def
ault)
     Metadata:
       title           : 5.1
Incompatible sample format 's16' for codec 'ac3', auto-selecting format 
'flt'
strptime() unavailable on this system, cannot convert the date string.
Output #0, matroska, to 'W:\transcode\tmp\tmp_enc_audio.mkv':
   Metadata:
     title           : Test
     creation_time   : 2012-09-01 21:31:06
     encoder         : Lavf54.3.100
     Stream #0:0(eng): Audio: ac3, 48000 Hz, 5.1(side), flt, 640 kb/s 
(default)
     Metadata:
       title           : 5.1
Stream mapping:
   Stream #0:0 -> #0:0 (dca -> ac3)
Press [q] to stop, [?] for help
size=  622740kB time=02:12:28.98 bitrate= 641.8kbits/s
video:0kB audio:621015kB global headers:0kB muxing overhead 0.277795%