[FFmpeg-user] Best way for converting HD 1080i to DVCPRO25 DV?

[Iban Garcia]

Hi Carl,

Here the info.

-b:v parameter is not needed for DV, because you can "set" the bitrate
using yuv411p (for DVCPRO25) or using yuv422p (for DVCPRO50),
indirectly.

The problem is the scaling (downscaling)... My question is about the
quality for transcoding from HD1080i to SD DVCPRO25. Is this (without
any filtering) the best way to process these contents to SD?

Many thanks

Iban

P.D.: If you need some more information, please, ask for it with no problem.



ffmpeg version N-39247-g6809818 Copyright (c) 2000-2012 the FFmpeg developers
  built on Mar 25 2012 17:35:24 with gcc 4.5.1 20101208
[gcc-4_5-branch revision 167585]
  configuration: --shlibdir=/usr/lib64 --prefix=/usr/local
--mandir=/usr/share/man --libdir=/usr/lib64 --enable-pthreads
--enable-shared --enable-libvorbis --enable-gpl --enable-x11grab
--enable-libx264 --enable-libmp3lame --enable-postproc
  libavutil      51. 44.100 / 51. 44.100
  libavcodec     54. 12.100 / 54. 12.100
  libavformat    54.  3.100 / 54.  3.100
  libavdevice    53.  4.100 / 53.  4.100
  libavfilter     2. 65.102 /  2. 65.102
  libswscale      2.  1.100 /  2.  1.100
  libswresample   0. 10.100 /  0. 10.100
  libpostproc    52.  0.100 / 52.  0.100
[mxf @ 0x6284e0] Unknown frame layout type: 1
Input #0, mxf, from
'/net/localhost/biltegia/hot_folders/_transcoding_intermediate/20120614_14575900_0005050650_001_001_LA_ISLA_DE_L_20120619_091913.mxf':
  Metadata:
    timecode        : 00:00:00:00
  Duration: 00:52:13.48, start: 0.000000, bitrate: 59995 kb/s
    Stream #0:0: Video: mpeg2video (4:2:2), yuv422p, 1920x1080 [SAR
1:1 DAR 16:9], 50000 kb/s, 25 fps, 25 tbr, 25 tbn, 50 tbc
    Stream #0:1: Audio: pcm_s24le, 48000 Hz, 1 channels, s32, 1152 kb/s
    Stream #0:2: Audio: pcm_s24le, 48000 Hz, 1 channels, s32, 1152 kb/s
    Stream #0:3: Audio: pcm_s24le, 48000 Hz, 1 channels, s32, 1152 kb/s
    Stream #0:4: Audio: pcm_s24le, 48000 Hz, 1 channels, s32, 1152 kb/s
    Stream #0:5: Audio: pcm_s24le, 48000 Hz, 1 channels, s32, 1152 kb/s
    Stream #0:6: Audio: pcm_s24le, 48000 Hz, 1 channels, s32, 1152 kb/s
    Stream #0:7: Audio: pcm_s24le, 48000 Hz, 1 channels, s32, 1152 kb/s
    Stream #0:8: Audio: pcm_s24le, 48000 Hz, 1 channels, s32, 1152 kb/s
[buffer @ 0x6283a0] w:1920 h:1080 pixfmt:yuv422p tb:1/1000000 sar:1/1 sws_param:
[scale @ 0x7903a0] w:1920 h:1080 fmt:yuv422p sar:1/1 -> w:720 h:576
fmt:yuv411p sar:64/45 flags:0x4
Output #0, dv, to
'/net/localhost/biltegia/hot_folders/_transcoding_intermediate/20120614_14575900_0005050650_001_001_LA_ISLA_DE_L_20120619_091913.dv':
  Metadata:
    timecode        : 00:00:00:00
    encoder         : Lavf54.3.100
    Stream #0:0: Video: dvvideo, yuv411p, 720x576 [SAR 64:45 DAR
16:9], q=2-31, 25000 kb/s, 90k tbn, 25 tbc
Stream mapping:
  Stream #0:0 -> #0:0 (mpeg2video -> dvvideo)
Press [q] to stop, [?] for help
[mpeg2video @ 0x744600] warning: first frame is no keyframe
frame=   19 fps=0.0 q=0.0 size=    2672kB time=00:00:00.76
bitrate=28800.0kbits/s
frame=   23 fps= 22 q=0.0 size=    3234kB time=00:00:00.92
bitrate=28800.0kbits/s
frame=   32 fps= 20 q=0.0 size=    4500kB time=00:00:01.28
bitrate=28800.0kbits/s
frame=   43 fps= 20 q=0.0 size=    6047kB time=00:00:01.72
bitrate=28800.0kbits/s
frame=   54 fps= 21 q=0.0 size=    7594kB time=00:00:02.16
bitrate=28800.0kbits/s
frame=   58 fps= 18 q=0.0 size=    8156kB time=00:00:02.32
bitrate=28800.0kbits/s

......................................................................................

frame=78228 fps= 63 q=0.0 size=11000812kB time=00:52:09.12
bitrate=28800.0kbits/s
frame=78267 fps= 63 q=0.0 size=11006297kB time=00:52:10.68
bitrate=28800.0kbits/s
frame=78303 fps= 63 q=0.0 size=11011359kB time=00:52:12.12
bitrate=28800.0kbits/s
frame=78337 fps= 63 q=0.0 Lsize=11016141kB time=00:52:13.48
bitrate=28800.0kbits/s
video:11016141kB audio:0kB global headers:0kB muxing overhead 0.000000%




2012/6/20 Carl Eugen Hoyos <cehoyos at ag.or.at>

> Iban Garcia <ibantxo28 <at> gmail.com> writes:
>
> > ffmpeg -y -threads 8 -i original_video.mxf -b:v 25000000 -s 720x576
> > -pix_fmt yuv411p -aspect 16:9 -an -r 25 output.dv
>
> (Complete, uncut console output missing.)
> I don't think you can set the bitrate for dv.
> Using yuv411p means you loose some colour information,
> I don't know if this is unavoidable for your use case.
>
> Carl Eugen
>
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