[FFmpeg-user] Using FFMPEG to encode multiple outputs in 'parallel' (doesn't work?)
DopeLabs
dopelabs at dubstep.fm
Thu Jul 6 13:44:45 EEST 2017
Option 2 in your question looks fine to me...
I have used ffmpeg to transcode audio and video streams before to achieve adaptive streaming.
Here is an example of an audio transcode... input is 256k mp3, output is 128k, 64k, and 24k
$ ffmpeg -i http://stream.dubstep.fm -c:a mp3 -b:a 128k -f null /dev/null -c:a mp3 -b:a 64k -f null /dev/null -c:a mp3 -b:a 24k -ar 22050 -f null /dev/null
ffmpeg version N-86413-g50be8f2142 Copyright (c) 2000-2017 the FFmpeg developers
built with Apple LLVM version 8.1.0 (clang-802.0.42)
configuration: --enable-libvidstab --enable-shared --enable-pthreads --cc=/usr/bin/clang --enable-vda --enable-videotoolbox --arch=x86_64 --enable-yasm --enable-gpl --enable-postproc --enable-libx264 --enable-libxvid --enable-filter=coreimage --enable-filter=coreimagesrc --enable-filter=frei0r --enable-filter=frei0r_src --enable-swscale --enable-avfilter --enable-avresample --enable-libmp3lame --enable-libvorbis --enable-libopus --enable-libtheora --enable-libopenjpeg --enable-libmodplug --enable-libvpx --enable-libsoxr --enable-libspeex --enable-libass --enable-libbluray --enable-lzma --enable-gnutls --enable-fontconfig --enable-libfreetype --enable-libfribidi --enable-libx265 --enable-version3 --enable-libwavpack --enable-libssh --enable-librtmp --enable-libfdk-aac --enable-nonfree --enable-libzmq --enable-opencl --enable-ffplay --enable-libcaca --enable-libvidstab
libavutil 55. 63.100 / 55. 63.100
libavcodec 57. 96.101 / 57. 96.101
libavformat 57. 72.101 / 57. 72.101
libavdevice 57. 7.100 / 57. 7.100
libavfilter 6. 91.100 / 6. 91.100
libavresample 3. 6. 0 / 3. 6. 0
libswscale 4. 7.101 / 4. 7.101
libswresample 2. 8.100 / 2. 8.100
libpostproc 54. 6.100 / 54. 6.100
[mp3 @ 0x7fa3b2000000] Skipping 88 bytes of junk at 0.
Input #0, mp3, from 'http://stream.dubstep.fm':
Metadata:
icy-genre : Dubstep, Dub, Electronic, Garage
icy-name : Dubstep.fm
icy-notice1 : <BR>This stream requires <a href="http://www.winamp.com">Winamp</a><BR>
icy-notice2 : SHOUTcast DNAS/posix(linux x64) v2.5.1.724<BR>
icy-pub : 1
icy-url : https://www.dubstep.fm
StreamTitle : ARCHIVE - 2011-01-09 - The Dented McStank With Phaded From Chicago
StreamUrl : https://www.dubstep.fm
Duration: N/A, start: 0.000000, bitrate: 256 kb/s
Stream #0:0: Audio: mp3, 44100 Hz, stereo, s16p, 256 kb/s
Stream mapping:
Stream #0:0 -> #0:0 (mp3 (native) -> mp3 (libmp3lame))
Stream #0:0 -> #1:0 (mp3 (native) -> mp3 (libmp3lame))
Stream #0:0 -> #2:0 (mp3 (native) -> mp3 (libmp3lame))
Press [q] to stop, [?] for help
Output #0, null, to '/dev/null':
Metadata:
icy-genre : Dubstep, Dub, Electronic, Garage
icy-name : Dubstep.fm
icy-notice1 : <BR>This stream requires <a href="http://www.winamp.com">Winamp</a><BR>
icy-notice2 : SHOUTcast DNAS/posix(linux x64) v2.5.1.724<BR>
icy-pub : 1
icy-url : https://www.dubstep.fm
StreamTitle : ARCHIVE - 2011-01-09 - The Dented McStank With Phaded From Chicago
StreamUrl : https://www.dubstep.fm
encoder : Lavf57.72.101
Stream #0:0: Audio: mp3 (libmp3lame), 44100 Hz, stereo, s16p, 128 kb/s
Metadata:
encoder : Lavc57.96.101 libmp3lame
Output #1, null, to '/dev/null':
Metadata:
icy-genre : Dubstep, Dub, Electronic, Garage
icy-name : Dubstep.fm
icy-notice1 : <BR>This stream requires <a href="http://www.winamp.com">Winamp</a><BR>
icy-notice2 : SHOUTcast DNAS/posix(linux x64) v2.5.1.724<BR>
icy-pub : 1
icy-url : https://www.dubstep.fm
StreamTitle : ARCHIVE - 2011-01-09 - The Dented McStank With Phaded From Chicago
StreamUrl : https://www.dubstep.fm
encoder : Lavf57.72.101
Stream #1:0: Audio: mp3 (libmp3lame), 44100 Hz, stereo, s16p, 64 kb/s
Metadata:
encoder : Lavc57.96.101 libmp3lame
Output #2, null, to '/dev/null':
Metadata:
icy-genre : Dubstep, Dub, Electronic, Garage
icy-name : Dubstep.fm
icy-notice1 : <BR>This stream requires <a href="http://www.winamp.com">Winamp</a><BR>
icy-notice2 : SHOUTcast DNAS/posix(linux x64) v2.5.1.724<BR>
icy-pub : 1
icy-url : https://www.dubstep.fm
StreamTitle : ARCHIVE - 2011-01-09 - The Dented McStank With Phaded From Chicago
StreamUrl : https://www.dubstep.fm
encoder : Lavf57.72.101
Stream #2:0: Audio: mp3 (libmp3lame), 22050 Hz, stereo, s16p, 24 kb/s
Metadata:
encoder : Lavc57.96.101 libmp3lame
size=N/A time=00:00:13.14 bitrate=N/A speed=2.69x
video:0kB audio:347kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
> On Jul 5, 2017, at 2:23 39PM, sh
> alin <shalin186 at gmail.com> wrote:
>
> Reuben Martin wrote
>> On Thursday, June 29, 2017 6:56:51 PM CDT shalin wrote:
>>> Cley Faye wrote
>>>
>>>> More to the point, as far as I know, ffmpeg will not do parallel
>>> treatment
>>>> on either input or output, as you deduced. It certainly is doable, but
>>>> don't seem trivial to implement in the ffmpeg CLI tool itself since
>>> that
>>>> tool must handle various cases, and introducing (more) special cases
>>> would
>>>> add complexity for not much benefits.
>>>>
>>>> You should look in using the various ffmpeg libraries directly; with
>>> that
>>>> you could probably write it to decode once, encode multiple time. But
>>>> unless you have shockingly similar settings and unlimited processing
>>>> power,
>>>> you'll most likely stall some of your encodings while other catch up
>>> with
>>>> them. I don't know how well ffmpeg libraries handle multithreading (I
>>>> suppose fairly well since most of it's operations are based on context
>>>> structures) but you'll have to do a fair amount of synchronization by
>>>> hand.
>>>
>>> Thank you for your answer to my original question. So from this, I am
>>> assuming that ffmpeg in its current form doesn't support output level
>>> parallelism. Actually I have 'shockingly' similar transcodings to perform
>>> on
>>> a given input stream (I need to crop different parts of the input video
>>> and
>>> encode them at same bitrate and also cropped parts are same in size for
>>> each stream). With that each encode should roughly run at the same rate
>>> and
>>> I believe multithreading should be really helpful.
>>
>> All this is possible but you need to do a lot of reading. Starting with
>> input
>> mapping. http://www.ffmpeg.org/ffmpeg-all.html#Advanced-options
>>
>> It couldn’t hurt to read up on how anonymous pipes work in a posix shell,
>> as
>> well as other shell related concepts.
>
> There's no doubt that I need a lot of reading but I wish you at least read
> my question properly. It has nothing to do with pipes or shell. It's about
> running multiple encodes in parallel within single ffmpeg process (option 2
> in my question). Simply providing the link doesn't help as it doesn't solve
> the issue at hand.
>
>
>
>
> --
> View this message in context: http://www.ffmpeg-archive.org/Using-FFMPEG-to-encode-multiple-outputs-in-parallel-doesn-t-work-tp4680420p4680482.html
> Sent from the FFmpeg-users mailing list archive at Nabble.com.
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