[FFmpeg-user] (mpeg2) how to set "audio delay relative to video" as 0 ?

linxs linxsy at gmail.com
Thu Sep 18 02:58:33 CEST 2014


D:\>ffprobe 0.mpg
ffprobe version N-63439-g96470ca Copyright (c) 2007-2014 the FFmpeg
developers
  built on May 25 2014 22:01:51 with gcc 4.8.2 (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-libcaca
--enable-libfreetyp
e --enable-libgme --enable-libgsm --enable-libilbc --enable-libmodplug
--enable-
libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb
--enable-libope
njpeg --enable-libopus --enable-librtmp --enable-libschroedinger
--enable-libsox
r --enable-libspeex --enable-libtheora --enable-libtwolame
--enable-libvidstab -
-enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis
--enable-libvpx
--enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265
--enable-
libxavs --enable-libxvid --enable-decklink --enable-zlib
  libavutil      52. 86.100 / 52. 86.100
  libavcodec     55. 65.100 / 55. 65.100
  libavformat    55. 41.100 / 55. 41.100
  libavdevice    55. 13.101 / 55. 13.101
  libavfilter     4.  5.100 /  4.  5.100
  libswscale      2.  6.100 /  2.  6.100
  libswresample   0. 19.100 /  0. 19.100
  libpostproc    52.  3.100 / 52.  3.100
Input #0, mpeg, from '0.mpg':
  Duration: 00:00:14.98, start: 0.529978, bitrate: 953 kb/s
    Stream #0:0[0x1e0]: Video: mpeg2video (Main), yuv420p(tv), 720x576 [SAR
16:1
5 DAR 4:3], max. 104857 kb/s, 25 fps, 25 tbr, 90k tbn, 50 tbc
    Stream #0:1[0x1c0]: Audio: mp2, 48000 Hz, stereo, s16p, 384 kb/s


I added -af "asetpts=PTS+0/TB" to the options of ffmpeg.
The audio delay relative to video of output mpg  is -10ms too. nothing
changed.


2014-09-17 20:10 GMT+08:00 Stefano Sabatini <stefasab at gmail.com>:

> On date Wednesday 2014-09-17 19:44:02 +0800, linxs wrote:
> > Hi everybody,
> > I transcode other video to mpg2 video as following command:
> > ffmpeg -i <other video> -c:v mpeg2video -b:v 8000k -c:a mp2 -y 0.mpg
> >
> >
> /****************************************************************************************************
> >
> /****************************************************************************************************
> > d:\>ffmpeg -i orig.mpg -c:v mpeg2video -c:a mp2 -y 0.mpg
> > ffmpeg version N-63439-g96470ca Copyright (c) 2000-2014 the FFmpeg
> > developers
> [...]
> > I use MediaInfo.exe to view the ouput mpg, and get the result:
> >
> >
> /****************************************************************************************************
> >
> /****************************************************************************************************
> > General
> > Complete name                            :
> > D:\1.project\1.HDPlayer\audiolevel\FM_MIRROR\loop\0.mpg
> > Format                                   : MPEG-PS
> > File size                                : 1.70 MiB
> > Duration                                 : 15s 24ms
> > Overall bit rate mode                    : Variable
> > Overall bit rate                         : 951 Kbps
> >
> > Video
> > ID                                       : 224 (0xE0)
> > Format                                   : MPEG Video
> > Format version                           : Version 2
> > Format profile                           : Main at Main
> > Format settings, BVOP                    : No
> > Format settings, Matrix                  : Default
> > Format settings, GOP                     : Variable
> > Duration                                 : 14s 960ms
> > Bit rate mode                            : Variable
> > Bit rate                                 : 548 Kbps
> > Width                                    : 720 pixels
> > Height                                   : 576 pixels
> > Display aspect ratio                     : 4:3
> > Frame rate                               : 25.000 fps
> > Standard                                 : PAL
> > Color space                              : YUV
> > Chroma subsampling                       : 4:2:0
> > Bit depth                                : 8 bits
> > Scan type                                : Progressive
> > Compression mode                         : Lossy
> > Bits/(Pixel*Frame)                       : 0.053
> > Time code of first frame                 : 00:00:00:00
> > Time code source                         : Group of pictures header
> > Stream size                              : 1 001 KiB (57%)
> >
> > Audio
> > ID                                       : 192 (0xC0)
> > Format                                   : MPEG Audio
> > Format version                           : Version 1
> > Format profile                           : Layer 2
> > Duration                                 : 15s 24ms
> > Bit rate mode                            : Constant
> > Bit rate                                 : 384 Kbps
> > Channel(s)                               : 2 channels
> > Sampling rate                            : 48.0 KHz
> > Compression mode                         : Lossy
> > Delay relative to video                  : -10ms
> >
> > >>>>>>>>>  !!!!!!! how to make this "delay relative to video" value to
> > 0ms?
>
> What values do you get with ffprobe? Did you try with the asetpts
> filter? This will require audio transcoding though.
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