[FFmpeg-user] Can I speed up transcoding?

Tue Jan 8 01:00:10 CET 2013

Dear Group:

I am encoding an FLV that is 1m39s long. It contains SPEEX audio and H.264
video. It was encoded at variable bit rate.

I successfully transcode it to MP4 (AAC audio, and H264 video) using the
following command.

ffmpeg -y -i
liveRecording/telecomcto05BC3D96-5AAE-B957-D4A5-16B9D6DAF813.flv -c:v
libx264 -crf 23 -preset superfast -vsync 1 -r 25 -c:a aac -strict -2 -b:a
16k -ar 16000 -ac 1 liveRecording/telecomcto16000-16k-superfast.mp4

The above command gives me the file size I need which is about 2/3 the
original FLV size, but it takes 1m44s to transcode.

Is there anything I can do to transcode faster?

FULL OUTPUT IS HERE:
ffmpeg -y -i
liveRecording/telecomcto05BC3D96-5AAE-B957-D4A5-16B9D6DAF813.flv -c:v
libx264 -crf 23 -preset superfast -vsync 1 -r 25 -c:a aac -strict -2 -b:a
16k -ar 16000 -ac 1 liveRecording/telecomcto16000-16k-superfast.mp4
ffmpeg version N-48604-ga572cc8 Copyright (c) 2000-2013 the FFmpeg
developers
  built on Jan  7 2013 14:26:13 with gcc 4.1.2 (GCC) 20080704 (Red Hat
4.1.2-52)
  configuration: --enable-gpl --enable-libmp3lame --enable-libvorbis
--enable-libvpx --enable-libx264 --enable-libspeex
  libavutil      52. 13.100 / 52. 13.100
  libavcodec     54. 86.100 / 54. 86.100
  libavformat    54. 59.106 / 54. 59.106
  libavdevice    54.  3.102 / 54.  3.102
  libavfilter     3. 32.100 /  3. 32.100
  libswscale      2.  1.103 /  2.  1.103
  libswresample   0. 17.102 /  0. 17.102
  libpostproc    52.  2.100 / 52.  2.100
Input #0, flv, from
'liveRecording/telecomcto05BC3D96-5AAE-B957-D4A5-16B9D6DAF813.flv':
  Metadata:
    creationdate    : Mon Jan 7 15:35:55
  Duration: 00:01:36.44, start: 0.000000, bitrate: 840 kb/s
    Stream #0:0: Video: h264 (Baseline), yuv420p, 640x480 [SAR 1:1 DAR
4:3], 30 tbr, 1k tbn, 60 tbc
    Stream #0:1: Audio: speex, 16000 Hz, mono, s16
[libx264 @ 0x1a20e60] using SAR=1/1
[libx264 @ 0x1a20e60] using cpu capabilities: MMX2 SSE2Fast SSSE3
FastShuffle SSE4.1 Cache64
[libx264 @ 0x1a20e60] profile High, level 3.0
[libx264 @ 0x1a20e60] 264 - core 129 r2230 1cffe9f - H.264/MPEG-4 AVC codec
- Copyleft 2003-2012 - http://www.videolan.org/x264.html - options: cabac=1
ref=1 deblock=1:0:0 analyse=0x3:0x3 me=dia subme=1 psy=1 psy_rd=1.00:0.00
mixed_ref=0 me_range=16 chroma_me=1 trellis=0 8x8dct=1 cqm=0 deadzone=21,11
fast_pskip=1 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=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=1
weightb=1 open_gop=0 weightp=1 keyint=250 keyint_min=25 scenecut=40
intra_refresh=0 rc=crf mbtree=0 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69
qpstep=4 ip_ratio=1.40 pb_ratio=1.30 aq=1:1.00
Output #0, mp4, to 'liveRecording/telecomcto16000-16k-superfast.mp4':
  Metadata:
    creationdate    : Mon Jan 7 15:35:55
    encoder         : Lavf54.59.106
    Stream #0:0: Video: h264 ([33][0][0][0] / 0x0021), yuv420p, 640x480
[SAR 1:1 DAR 4:3], q=-1--1, 12800 tbn, 25 tbc
    Stream #0:1: Audio: aac ([64][0][0][0] / 0x0040), 16000 Hz, mono, fltp,
16 kb/s
Stream mapping:
  Stream #0:0 -> #0:0 (h264 -> libx264)
  Stream #0:1 -> #0:1 (libspeex -> aac)
Press [q] to stop, [?] for help
frame= 2413 fps= 23 q=20.0 Lsize=    6995kB time=00:01:36.51 bitrate=
593.7kbits/s dup=209 drop=0
video:6724kB audio:209kB subtitle:0 global headers:0kB muxing overhead
0.884337%
[libx264 @ 0x1a20e60] frame I:10    Avg QP:17.86  size: 39319
[libx264 @ 0x1a20e60] frame P:609   Avg QP:19.24  size:  6757
[libx264 @ 0x1a20e60] frame B:1794  Avg QP:20.80  size:  1325
[libx264 @ 0x1a20e60] consecutive B-frames:  0.8%  0.1%  0.1% 99.0%
[libx264 @ 0x1a20e60] mb I  I16..4:  6.1% 18.3% 75.6%
[libx264 @ 0x1a20e60] mb P  I16..4:  1.0%  1.2%  0.2%  P16..4: 80.6%  0.0%
 0.0%  0.0%  0.0%    skip:16.9%
[libx264 @ 0x1a20e60] mb B  I16..4:  0.1%  0.1%  0.0%  B16..8: 17.6%  0.0%
 0.0%  direct:20.8%  skip:61.3%  L0:37.5% L1:56.5% BI: 6.0%
[libx264 @ 0x1a20e60] 8x8 transform intra:37.2% inter:24.9%
[libx264 @ 0x1a20e60] coded y,uvDC,uvAC intra: 50.5% 72.3% 44.1% inter:
8.7% 34.1% 6.9%
[libx264 @ 0x1a20e60] i16 v,h,dc,p: 63%  5% 15% 17%
[libx264 @ 0x1a20e60] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 53%  9% 14%  3%  2%
 7%  2%  7%  3%
[libx264 @ 0x1a20e60] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 33% 20% 11%  6%  6%
 6%  6%  6%  6%
[libx264 @ 0x1a20e60] i8c dc,h,v,p: 38% 21% 29% 12%
[libx264 @ 0x1a20e60] Weighted P-Frames: Y:0.2% UV:0.0%
[libx264 @ 0x1a20e60] kb/s:570.65

-- 
_________________________________________
Leo Papadopoulos (leo at telecomcto.com)
TelecomCTO, LLC <http://telecomcto.com>
Virtual Number: +1(203)539-0448
Linkedin <https://www.linkedin.com/in/leopapadopoulos> -
Twitter<https://twitter.com/LeoP_TCTO>