[FFmpeg-user] How do I make ffplay play without high latency?

ved kpl ved.kpl at gmail.com
Fri Nov 23 20:57:44 CET 2012


did you check if you are getting similar issue with other application?
like an app based on gstreamer?

On Fri, Nov 23, 2012 at 11:33 AM, Jesse Gordon <tojesseg at gmail.com> wrote:
>
> On 11/22/2012 11:01 AM, Nicolas George wrote:
>>
>> Le duodi 2 frimaire, an CCXXI, Jesse Gordon a écrit :
>>>>
>>>> ffmpeg ... -f sdl -
>>>
>>> .....
>>>
>>> It looks like (from the man page) that low_delay is only an encoding
>>> option for motion encoding or something - but I could be wrong.
>>
>> The flags for the "low_delay" option seem to indicate it is relevant both
>> for encoding and decoding, and I see a lot of decoders actually checking
>> it.
>>
>> Again, trying it to see if it makes a difference is the most efficient
>> course of action.
>>
>> Regards,
>>
>
> Like this?
>
> ffmpeg -i test.flv -f sdl -
>
> (Didn't seem to work -- see below.)
>
> (This is the static build from Burek.)
>
> Actually, you've got me to thinking: if I can make ffmpeg (or ffplay) output
> a PNM image stream (or other raw image format) I can pipe it into my
> existing XVIDEO raw image stream player. Or can I make ffplay or ffmpeg spit
> out YUV frames directly?
>
> (I have a simple C program that reads a PNM image stream in stdin, converts
> it to YUV and displays it with XVIDEO. It's reasonably efficient and
> low-latency.
>
> However it seems more simple to just tell ffmpeg to "play as fast as
> possible." I guess if it doesn't already have a -benchmark type option it
> would be easy enough to add one.
>
> I looked through ffplay.c to try to find where I could comment out a call to
> the frame delay routine but couldn't find it. Anyone have a function name I
> could look for?
>
> I did try -vf "setpts=(PTS*0.9)" which make sit play a bit faster -- which
> does let the playing catch up with the streaming -- but then it still seems
> to stop and buffer in order to try to maintain the desired frame rate.
>
> Thanks,
>
> ~Jesse
>
> root at gatewaylaptop:/big# ffmpeg -i test.flv -f sdl -
> ffmpeg version N-46821-g8ad9b48 Copyright (c) 2000-2012 the FFmpeg
> developers
>   built on Nov 17 2012 05:11:19 with gcc 4.6 (Debian 4.6.3-1)
>   configuration: --prefix=/root/ffmpeg-static/32bit --arch=x86_32
> --extra-cflags='-m32 -I/root/ffmpeg-static/32bit/include -static'
> --extra-ldflags='-m32 -L/root/ffmpeg-static/32bit/lib -static'
> --extra-libs='-lxml2 -lexpat -lfreetype' --enable-static --disable-shared
> --disable-ffserver --disable-doc --enable-bzlib --enable-zlib
> --enable-postproc --enable-runtime-cpudetect --enable-libx264 --enable-gpl
> --enable-libtheora --enable-libvorbis --enable-libmp3lame --enable-gray
> --enable-libass --enable-libfreetype --enable-libopenjpeg --enable-libspeex
> --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-version3
> --enable-libvpx
>   libavutil      52.  7.100 / 52.  7.100
>   libavcodec     54. 71.100 / 54. 71.100
>   libavformat    54. 36.100 / 54. 36.100
>
>   libavdevice    54.  3.100 / 54.  3.100
>   libavfilter     3. 23.100 /  3. 23.100
>
>   libswscale      2.  1.102 /  2.  1.102
>   libswresample   0. 16.100 /  0. 16.100
>   libpostproc    52.  1.100 / 52.  1.100
> Input #0, flv, from 'test.flv':
>   Metadata:
>     major_brand     : mp42
>     minor_version   : 1
>     compatible_brands: mp42avc1
>     creation_time   : 2012-07-29 15:04:46
>     comment         : CAMCORDER BW10
>     comment-eng     : CAMCORDER BW10
>     encoder         : Lavf52.100.1
>   Duration: 00:01:02.25, start: 0.000000, bitrate: 7918 kb/s
>     Stream #0:0: Video: flv1, yuv420p, 1280x720, 7680 kb/s, 29.97 tbr, 1k
> tbn, 1k tbc
>     Stream #0:1: Audio: mp3, 44100 Hz, stereo, s16, 256 kb/s
> [NULL @ 0x969e160] Requested output format 'sdl' is not a suitable output
> format
> pipe:: Invalid argument
> root at gatewaylaptop:/big#
>
>
>
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