[FFmpeg-user] -movflags +faststart has no effect

[Ulf Zibis]

Hi,

from option -movflags +faststart I expect, that I can start playing the
video, even the encoding process has not finished yet.
But this does not work,why?

If I encode a video without -movflags +faststart and kill the process
with Ctrl-C after a while the video surprisingly is playable.

So there seems it doesn't matter if I use it or not.

Also I'm wondering where to find this option in the ffmpeg
documentation, I only find it in the wiki.

Here the output:

$ ffmpeg -i 20200205_161649.mp4 -vf scale=w=iw/2:h=ih/2 -movflags
+faststart 20200205_161649_2_f.mp4
ffmpeg version 4.2-static https://johnvansickle.com/ffmpeg/ Copyright
(c) 2000-2019 the FFmpeg developers
   built with gcc 6.3.0 (Debian 6.3.0-18+deb9u1) 20170516
   configuration: --enable-gpl --enable-version3 --enable-static
--disable-debug --disable-ffplay --disable-indev=sndio
--disable-outdev=sndio --cc=gcc-6 --enable-fontconfig --enable-frei0r
--enable-gnutls --enable-gmp --enable-libgme --enable-gray
--enable-libaom --enable-libfribidi --enable-libass --enable-libvmaf
--enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb
--enable-libopencore-amrwb --enable-libopenjpeg --enable-librubberband
--enable-libsoxr --enable-libspeex --enable-libsrt --enable-libvorbis
--enable-libopus --enable-libtheora --enable-libvidstab
--enable-libvo-amrwbenc --enable-libvpx --enable-libwebp
--enable-libx264 --enable-libx265 --enable-libxml2 --enable-libdav1d
--enable-libxvid --enable-libzvbi --enable-libzimg
   libavutil      56. 31.100 / 56. 31.100
   libavcodec     58. 54.100 / 58. 54.100
   libavformat    58. 29.100 / 58. 29.100
   libavdevice    58.  8.100 / 58.  8.100
   libavfilter     7. 57.100 /  7. 57.100
   libswscale      5.  5.100 /  5.  5.100
   libswresample   3.  5.100 /  3.  5.100
   libpostproc    55.  5.100 / 55.  5.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '20200205_161649.mp4':
   Metadata:
     major_brand     : isom
     minor_version   : 512
     compatible_brands: isomiso2avc1mp41
     encoder         : Lavf58.29.100
   Duration: 00:04:08.84, start: 0.000000, bitrate: 17268 kb/s
     Stream #0:0(eng): Video: h264 (High) (avc1 / 0x31637661), yuv420p,
1920x1080, 17004 kb/s, SAR 1:1 DAR 16:9, 30.01 fps, 30 tbr, 90k tbn,
180k tbc (default)
     Metadata:
       handler_name    : VideoHandle
     Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz,
stereo, fltp, 256 kb/s (default)
     Metadata:
       handler_name    : SoundHandle
Stream mapping:
   Stream #0:0 -> #0:0 (h264 (native) -> h264 (libx264))
   Stream #0:1 -> #0:1 (aac (native) -> aac (native))
Press [q] to stop, [?] for help
[libx264 @ 0x624bd00] using SAR=1/1
[libx264 @ 0x624bd00] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.1
Cache64
[libx264 @ 0x624bd00] profile Progressive High, level 3.1, 4:2:0, 8-bit
[libx264 @ 0x624bd00] 264 - core 157 r2969 d4099dd - H.264/MPEG-4 AVC
codec - Copyleft 2003-2019 - http://www.videolan.org/x264.html -
options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7
psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1
8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=3
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=2 keyint=250
keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf
mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40
aq=1:1.00
Output #0, mp4, to '20200205_161649_2_f.mp4':
   Metadata:
     major_brand     : isom
     minor_version   : 512
     compatible_brands: isomiso2avc1mp41
     encoder         : Lavf58.29.100
     Stream #0:0(eng): Video: h264 (libx264) (avc1 / 0x31637661),
yuv420p, 960x540 [SAR 1:1 DAR 16:9], q=-1--1, 30 fps, 15360 tbn, 30 tbc
(default)
     Metadata:
       handler_name    : VideoHandle
       encoder         : Lavc58.54.100 libx264
     Side data:
       cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
     Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz,
stereo, fltp, 128 kb/s (default)
     Metadata:
       handler_name    : SoundHandle
       encoder         : Lavc58.54.100 aac
frame=    6 fps=0.0 q=0.0 size=       0kB time=00:00:00.21 bitrate=  
1.8kbits/sframe=   18 fps= 17 q=0.0 size=       0kB time=00:00:00.61
bitrate=   0.6kbits/sframe=   27 fps= 17 q=0.0 size=       0kB
time=00:00:00.91 bitrate=   0.4kbits/sframe=   37 fps= 18 q=0.0
size=       0kB time=00:00:01.23 bitrate= 0.3kbits/sframe=   46 fps= 18
q=0.0 size=       0kB time=00:00:01.51 bitrate=   0.3kbits/sframe=   48
fps= 15 q=29.0 size=       0kB time=00:00:01.60 bitrate=  
0.2kbits/frame=   51 fps= 13 q=29.0 size=       0kB time=00:00:01.70
bitrate= 0.2kbits/frame=   54 fps= 12 q=29.0 size=       0kB
time=00:00:01.81 bitrate=   0.2kbits/frame=   58 fps= 12 q=29.0
size=       0kB time=00:00:01.94 bitrate=   0.2kbits/frame=   62 fps= 11
q=29.0 size=       0kB time=00:00:02.06 bitrate= 0.2kbits/frame=   65
fps= 10 q=29.0 size=       0kB time=00:00:02.17 bitrate=  
0.2kbits/frame=   69 fps=9.8 q=29.0 size=       0kB time=00:00:02.30
bitrate=   0.2kbits/frame=   73 fps=9.4 q=29.0 size=     256kB
time=00:00:02.43 bitrate= 862.5kbits/frame=   77 fps=9.0 q=29.0
size=     256kB time=00:00:02.58 bitrate= 812.6kbits/frame=   81 fps=8.7
q=29.0 size=     256kB time=00:00:02.70 bitrate= 774.2kbits/frame=   85
fps=8.5 q=29.0 size=     256kB time=00:00:02.83 bitrate= 739.3kbits/


-Ulf

--
Von meinem Seibert gesendet