Realtime output from ffmpeg and livestreamer using subprocess.Popen - python-2.7

Question

In ffmpeg and livestreamer i only get a few lines in realtime then i get the rest of them when the process is done...
I have tried two codes:
from subprocess import *
p = Popen('ffmpeg -i infile.mp4 outfile.mp4', stderr=STDOUT, stdout=PIPE)
for line in iter(p.stdout.readline(), b'')
print line.rstrip()
and
from subprocess import *
p = Popen('ffmpeg -i infile.mp4 outfile.mp4', stderr=STDOUT, stdout=PIPE)
while p.poll is None:
line = p.stdout.readline()
print line.rstrip()
Both of them prints first:
ffmpeg version N-72805-g913685f Copyright (c) 2000-2015 the FFmpeg developers
built with gcc 4.9.2 (GCC)
configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-av
isynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enab
le-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --
enable-libdcadec --enable-libfreetype --enable-libgme --enable-libgsm --enable-l
ibilbc --enable-libmodplug --enable-libmfx --enable-libmp3lame --enable-libopenc
ore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --ena
ble-librtmp --enable-libschroedinger --enable-libsoxr --enable-libspeex --enable
-libtheora --enable-libtwolame --enable-libvidstab --enable-libvo-aacenc --enabl
e-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable
-libwebp --enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --e
nable-lzma --enable-decklink --enable-zlib
libavutil 54. 27.100 / 54. 27.100
libavcodec 56. 41.100 / 56. 41.100
libavformat 56. 36.100 / 56. 36.100
libavdevice 56. 4.100 / 56. 4.100
libavfilter 5. 16.101 / 5. 16.101
libswscale 3. 1.101 / 3. 1.101
libswresample 1. 2.100 / 1. 2.100
libpostproc 53. 3.100 / 53. 3.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'a.mp4':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2avc1mp41
encoder : Lavf56.10.100
Duration: 01:34:36.14, start: 0.021333, bitrate: 6205 kb/s
Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1280x720,
5938 kb/s, 30 fps, 30 tbr, 15360 tbn, 60 tbc (default)
Metadata:
handler_name : VideoHandler
Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, flt
p, 256 kb/s (default)
Metadata:
handler_name : SoundHandler
[mp4 # 05013ce0] Codec for stream 0 does not use global headers but container fo
rmat requires global headers
[mp4 # 05013ce0] Codec for stream 1 does not use global headers but container fo
rmat requires global headers
Output #0, mp4, to 'b.mp4':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2avc1mp41
encoder : Lavf56.36.100
Stream #0:0(und): Video: h264 ([33][0][0][0] / 0x0021), yuv420p, 1280x720, q
=2-31, 5938 kb/s, 30 fps, 30 tbr, 15360 tbn, 15360 tbc (default)
Metadata:
handler_name : VideoHandler
Stream #0:1(und): Audio: aac ([64][0][0][0] / 0x0040), 48000 Hz, stereo, 256
kb/s (default)
Metadata:
handler_name : SoundHandler
Stream mapping:
Stream #0:0 -> #0:0 (copy)
Stream #0:1 -> #0:1 (copy)
Press [q] to stop, [?] for help
Then when the convert process is done the rest of the log turns up...
How can i get all stdout in realtime??
EDIT:
If i use a text file to write to it get all in realtime.
from subprocess import *
out_file = open('stdout.txt','a')
Popen('ffmpeg -i infile.mp4 outfile.mp4', stderr=STDOUT, stdout=out_file)
But i want it print out stdout in realtime..
Why does it work in realtime to a file but not direct print?

Answer 1

please check this out:
https://stackoverflow.com/a/2358686/1314124
The reason why it can't be printed is because "ffmpeg never prints one line, the status is updated by writing \r (carrige return) and then writing the line again. "