[FFmpeg-user] dvd ntsc complaint mpg2 with lower than preset rate

[Jim Shupert]

Friends,
I wish to know the full parameters that i need to declare to make a dvd
compliant mpg2 that I can author with dvdauthor

I have success using the preset -target ntsc-dvd

but I have some content that is 3 hours long.

I wish to lower the data rate to ~ 4.5 Mbps

I find I can use a -maxrate of 6mbps but if i go below 6 mbps it fails

the below seems to fail

ffmpeg -y -i /media/data/dvd-m/Hunt-003-b.mpg  -vcodec mpeg2video -pix_fmt
yuv420p -target ntsc-dvd -sample_fmt flt -maxrate 4500k -minrate 1200k
-aspect 4:3 /media/data/dvd-m/Hunt-003.mpg
ffmpeg version git-2012-09-24-fd63c2f Copyright (c) 2000-2012 the FFmpeg
developers
   built on Sep 24 2012 14:09:13 with gcc 4.4.3 (Ubuntu 4.4.3-4ubuntu5.1)
   configuration: --enable-gpl --enable-libfaac --enable-libmp3lame
--enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libtheora
--enable-libvorbis --enable-libvpx --enable-libx264 --enable-nonfree
--enable-version3 --enable-x11grab
   libavutil      51. 73.101 / 51. 73.101
   libavcodec     54. 58.100 / 54. 58.100
   libavformat    54. 28.101 / 54. 28.101
   libavdevice    54.  2.101 / 54.  2.101
   libavfilter     3. 17.100 /  3. 17.100
   libswscale      2.  1.101 /  2.  1.101
   libswresample   0. 15.100 /  0. 15.100
   libpostproc    52.  0.100 / 52.  0.100
[mpeg @ 0x282d240] max_analyze_duration 5000000 reached at 5005000
Input #0, mpeg, from '/media/data/dvd-m/Hunt-003-b.mpg':
   Duration: 02:02:21.53, start: 0.994667, bitrate: 7582 kb/s
     Stream #0:0[0x1e0]: Video: mpeg2video (Main), yuv420p, 720x480 [SAR
8:9 DAR 4:3], 9000 kb/s, 29.97 fps, 29.97 tbr, 90k tbn, 59.94 tbc
     Stream #0:1[0x80]: Audio: ac3, 48000 Hz, stereo, s16, 448 kb/s
[mpeg2video @ 0x282e4e0] Warning min_rate > 0 but min_rate != max_rate
isn't recommended!
[mpeg2video @ 0x282e4e0] bitrate above max bitrate
Output #0, dvd, to '/media/data/dvd-m/Hunt-003.mpg':
     Stream #0:0: Video: mpeg2video, yuv420p, 720x480 [SAR 8:9 DAR 4:3],
q=2-31, 6000 kb/s, 90k tbn, 29.97 tbc
     Stream #0:1: Audio: none, 48000 Hz, stereo, flt
Stream mapping:
   Stream #0:0 -> #0:0 (mpeg2video -> mpeg2video)
   Stream #0:1 -> #0:1 (ac3 -> ac3)
Error while opening encoder for output stream #0:0 - maybe incorrect
parameters such as bit_rate, rate, width or height

-----------------------------------
  basically I wish to come from an avi to a dvd compliant ( dvdauthor
compliant with nav packs ) mpg2 that has a definable datarate
not using the datarate in the preset -target ntsc-dvd

thanks