[FFmpeg-user] Problem generating clip from mpg files

Mike Grishaber mgrishaber at merlinone.com
Fri Jun 16 04:06:24 EEST 2017


Hello All,

 

I am extracting a clip from an mpg video using the following command and the
FFMpeg Windows build downloaded today on Windows 10.

ffmpeg.exe -i 271b.mpg -ss 00:00:05.000 -t 00:00:03.200 -c copy out_271b.mpg

 

I am using the copy parameter to avoid reencoding the clip.

The resulting mpg file only has the audio track, no video.

The following is the FFMpeg screen dump.

 

C:\ffmpeg-20170615\bin>ffmpeg.exe -i 271b.mpg -ss 00:00:05.000 -t
00:00:03.200 -c copy out_271b.mpg

ffmpeg version N-86482-gbc40674 Copyright (c) 2000-2017 the FFmpeg
developers

  built with gcc 7.1.0 (GCC)

  configuration: --disable-static --enable-shared --enable-gpl
--enable-version3 --enable-cuda --enable-cuvid --enable-d3d11va
--enable-dxva2 --enable-libmfx --enable-nvenc --enable-avisynth
--enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls
--enable-iconv --enable-libass --enable-libbluray --enable-libbs2b
--enable-libcaca --enable-libfreetype --enable-libgme --enable-libgsm
--enable-libilbc --enable-libmodplug --enable-libmp3lame
--enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenh264
--enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libsnappy
--enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame
--enable-libvidstab --enable-libvo-amrwbenc --enable-libvorbis
--enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264
--enable-libx265 --enable-libxavs --enable-libxvid --enable-libzimg
--enable-lzma --enable-zlib

  libavutil      55. 66.100 / 55. 66.100

  libavcodec     57. 99.100 / 57. 99.100

  libavformat    57. 73.100 / 57. 73.100

  libavdevice    57.  7.100 / 57.  7.100

  libavfilter     6. 92.100 /  6. 92.100

  libswscale      4.  7.101 /  4.  7.101

  libswresample   2.  8.100 /  2.  8.100

  libpostproc    54.  6.100 / 54.  6.100

Input #0, mpeg, from '271b.mpg':

  Duration: 00:01:11.44, start: 0.460000, bitrate: 2154 kb/s

    Stream #0:0[0x1e0]: Video: mpeg2video (Main), yuv420p(tv, bt470bg,
progressive), 640x480 [SAR 1:1 DAR 4:3], 2000 kb/s, 25 fps, 25 tbr, 90k tbn,
50 tbc

    Stream #0:1[0x1c0]: Audio: mp2, 44100 Hz, mono, s16p, 128 kb/s

[mpeg @ 0000000000666aa0] VBV buffer size not set, using default size of
130KB

If you want the mpeg file to be compliant to some specification

Like DVD, VCD or others, make sure you set the correct buffer size

Output #0, mpeg, to 'out_271b.mpg':

  Metadata:

    encoder         : Lavf57.73.100

    Stream #0:0: Video: mpeg2video (Main), yuv420p(tv, bt470bg,
progressive), 640x480 [SAR 1:1 DAR 4:3], q=2-31, 2000 kb/s, 25 fps, 25 tbr,
90k tbn, 25 tbc

    Stream #0:1: Audio: mp2, 44100 Hz, mono, s16p, 128 kb/s

Stream mapping:

  Stream #0:0 -> #0:0 (copy)

  Stream #0:1 -> #0:1 (copy)

Press [q] to stop, [?] for help

frame=   74 fps=0.0 q=-1.0 Lsize=     786kB time=00:00:03.17
bitrate=2027.2kbits/s speed= 198x

video:730kB audio:50kB subtitle:0kB other streams:0kB global headers:0kB
muxing overhead: 0.843343%

 

The following is the MediaInfo dump for the original file

General

Complete name                            :
C:\Raidshare\VidHiRes\PDIR0000\271b.mpg

Format                                   : MPEG-PS

File size                                : 18.3 MiB

Duration                                 : 1 min 11 s

Overall bit rate mode                    : Constant

Overall bit rate                         : 2 154 kb/s

 

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                     : N=11

Duration                                 : 1 min 11 s

Bit rate mode                            : Constant

Bit rate                                 : 2 000 kb/s

Width                                    : 640 pixels

Height                                   : 480 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)                       : 0.260

Time code of first frame                 : 00:00:00:00

Time code source                         : Group of pictures header

GOP, Open/Closed                         : Closed

Stream size                              : 16.9 MiB (92%)

Color primaries                          : BT.601 PAL

Transfer characteristics                 : BT.470 System B, BT.470 System G

Matrix coefficients                      : BT.601

 

Audio

ID                                       : 192 (0xC0)

Format                                   : MPEG Audio

Format version                           : Version 1

Format profile                           : Layer 2

Duration                                 : 1 min 11 s

Bit rate mode                            : Constant

Bit rate                                 : 128 kb/s

Channel(s)                               : 1 channel

Sampling rate                            : 44.1 kHz

Compression mode                         : Lossy

Stream size                              : 1.09 MiB (6%)

 

 

And this is the MediaInfo dump from the generated clip.

General

Complete name                            :
C:\ffmpeg-20170615\bin\out_271b.mpg

Format                                   : MPEG-PS

File size                                : 786 KiB

Duration                                 : 3 s 187 ms

Overall bit rate mode                    : Constant

Overall bit rate                         : 2 020 kb/s

 

Audio

ID                                       : 192 (0xC0)

Format                                   : MPEG Audio

Format version                           : Version 1

Format profile                           : Layer 2

Duration                                 : 3 s 187 ms

Bit rate mode                            : Constant

Bit rate                                 : 128 kb/s

Channel(s)                               : 1 channel

Sampling rate                            : 44.1 kHz

Compression mode                         : Lossy

Stream size                              : 49.8 KiB (6%)

 

Thanks for your help.

 

 

 



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