[FFmpeg-user] Setting audio delay when remuxing mpegts to mpegps

[Georgi Chorbadzhiyski]

Guys I'm remuxing mpegts files into mpegps (-f vob) and the problem I'm having is that
mediainfo reports for the audio "Delay relative to video: -146ms"

Is there a way for this delay to be 0 (or at lease less that 40 ms) without
recompressing?

file1.ts, file2, and file3.ts each are 1 minute long.

cat file1.ts file2.ts file3.ts | \
  ./ffmpeg -f mpegts -i - -ss 00:01:00.000 -acodec copy -vcodec copy -vframes 1525 -f vob -y file.mpg

> ffmpeg version N-35458-g51177b1, Copyright (c) 2000-2011 the FFmpeg developers
>   built on Dec  5 2011 16:09:01 with gcc 4.5.3
>   configuration: --enable-gpl --enable-pic --enable-libx264
>   libavutil    51. 30. 0 / 51. 30. 0
>   libavcodec   53. 40. 0 / 53. 40. 0
>   libavformat  53. 24. 0 / 53. 24. 0
>   libavdevice  53.  4. 0 / 53.  4. 0
>   libavfilter   2. 51. 0 /  2. 51. 0
>   libswscale    2.  1. 0 /  2.  1. 0
>   libpostproc  51.  2. 0 / 51.  2. 0
> [mp3 @ 0x14277e0] Header missing
> [mpegts @ 0x13ff7e0] max_analyze_duration 5000000 reached at 5016000                                                                                                  
> [mpegts @ 0x13ff7e0] Estimating duration from bitrate, this may be inaccurate                                                                                         
> Input #0, mpegts, from 'pipe:':                                                                                                                                       
>   Duration: N/A, start: 94570.689189, bitrate: 10160 kb/s
>   Program 1007 
>     Metadata:
>       service_name    : bTV
>       service_provider: BULSATCOM
>     Stream #0:0[0x50]: Video: mpeg2video (Main) ([2][0][0][0] / 0x0002), yuv420p, 720x576 [SAR 16:15 DAR 4:3], 10000 kb/s, 25 fps, 25 tbr, 90k tbn, 50 tbc
>     Stream #0:1[0x51](bul): Audio: mp2 ([4][0][0][0] / 0x0004), 48000 Hz, stereo, s16, 160 kb/s
> Output #0, vob, to 'file.mpg':
>   Metadata:
>     encoder         : Lavf53.24.0
>     Stream #0:0: Video: mpeg2video ([2][0][0][0] / 0x0002), yuv420p, 720x576 [SAR 16:15 DAR 4:3], q=2-31, 10000 kb/s, 25 fps, 90k tbn, 25 tbc
>     Stream #0:1(bul): Audio: mp2 ([4][0][0][0] / 0x0004), 48000 Hz, stereo, 160 kb/s
> Stream mapping:
>   Stream #0:0 -> #0:0 (copy)
>   Stream #0:1 -> #0:1 (copy)
> frame= 1526 fps=  0 q=-1.0 Lsize=   18630kB time=00:01:00.67 bitrate=2515.4kbits/s    
> video:17211kB audio:1185kB global headers:0kB muxing overhead 1.273521%

Media info reports for file.mpg

> General
> Complete name                            : file.mpg
> Format                                   : MPEG-PS
> File size                                : 18.2 MiB
> Duration                                 : 1mn 1s
> Overall bit rate mode                    : Variable
> Overall bit rate                         : 2 502 Kbps
> 
> Video
> ID                                       : 224 (0xE0)
> Format                                   : MPEG Video
> Format version                           : Version 2
> Format profile                           : Main at Main
> Format settings, BVOP                    : Yes
> Format settings, Matrix                  : Custom
> Format settings, GOP                     : M=3, N=12
> Duration                                 : 1mn 1s
> Bit rate mode                            : Variable
> Bit rate                                 : 2 292 Kbps
> Maximum bit rate                         : 10 000 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                                : Interlaced
> Scan order                               : Top Field First
> Compression mode                         : Lossy
> Bits/(Pixel*Frame)                       : 0.221
> Stream size                              : 16.7 MiB (92%)
> 
> Audio
> ID                                       : 192 (0xC0)
> Format                                   : MPEG Audio
> Format version                           : Version 1
> Format profile                           : Layer 2
> Duration                                 : 1mn 0s
> Bit rate mode                            : Constant
> Bit rate                                 : 160 Kbps
> Channel(s)                               : 2 channels
> Sampling rate                            : 48.0 KHz
> Compression mode                         : Lossy
> Delay relative to video                  : -146ms

Can this be lower or zero?

> Stream size                              : 1.16 MiB (6%)

-- 
Georgi Chorbadzhiyski
http://georgi.unixsol.org/