On Wed, 10 May 2006, Levi Bard wrote:
>> Found allowed resolutions for DVD:
>>
>> ,--
>> | Note that the DVD format only specifically supports 720x480,
>> | 704x480, 352x480, and 352x240 resolutions for NTSC
>> '--
>> So, assuming I can get the video recorded in one of those (which I can), do
>> you know a way to skip the recoding step? It seems like the video goes
>> through a lot of transformations; that can't be good for it.
>
> The only one I've actually recorded video with (on dvd) is 720x480, so
> I can't give a definitive answer about the other resolutions.
It's from dvdauthor(1). I'll treal that as gospel.
>> But, when I re-extract the sound from the vob and check its level, it's
>> around half as loud as when it went in (not exactly half; then I'd be
>> REALLY suspicious). Is this an artifact of the conversion to ac3, or is
>> there some option that I don't notice that controls this?
>
> When you recombine the files with ffmpeg, does it show two audio
> tracks?
No:
Input #0, mpeg, from 'movie.mpg':
Duration: 02:09:52.1, start: 0.155878, bitrate: 2281 kb/s
Stream #0.0[0x1c0]: Audio: mp2, 48000 Hz, stereo, 224 kb/s
Stream #0.1[0x1e0]: Video: mpeg2video, yuv420p, 352x240, 29.97 fps, 2000 kb/s
Input #1, wav, from 'sound.wav':
Duration: 02:09:52.8, start: 0.000000, bitrate: 1536 kb/s
Stream #1.0: Audio: pcm_s16le, 48000 Hz, stereo, 1536 kb/s
Assuming NTSC for target.
Output #0, dvd, to 'movie-352x240.vob':
Stream #0.0: Video: mpeg2video, yuv420p, 352x240, 29.97 fps, q=2-31, 4000 kb/s
Stream #0.1: Audio: ac3, 48000 Hz, stereo, 448 kb/s
Stream mapping:
Stream #0.1 -> #0.0
Stream #1.0 -> #0.1
That's what the "-map" options control. It took a bit of fiddling to get
them right.
> If not, I might try doing the mapping to the new resolution with
> ffmpeg first, then demuxing the video and audio using mpgdemux (part
> of the mpgtx package), then normalizing the audio as you've done,
> converting to ac3 or mp2, then remuxing with mplex (part of the
> mjpegtools package).
>
> Kind of a PITA, I know - such is the joy of video authoring.
Yeah. Rule #1: Keep your source & destination files on IDE, not USB,
drives.
Rule #2: If one of them _is_ on USB, don't have _both_ of them on USB.
Seems rather hard on the quality, going through all those recompressions.
Unless mpgdemux/mplex can be convinced not to recompress, just leave the
format alone?
The sox step doesn't involve any extra recompression steps, as it's already
going from mp2 -> linear -> ac3, I just change that to mp2 -> linear ->
louder linear -> ac3.
-- -eben ebQenW1@EtaRmpTabYayU.rIr.OcoPm home.tampabay.rr.com/hactarAnd we never failed to fail / It was the easiest thing to do -- CSN ----------------------------------------------------------------------- This list is provided as an unmoderated internet service by Networked Knowledge Systems (NKS). Views and opinions expressed in messages posted are those of the author and do not necessarily reflect the official policy or position of NKS or any of its employees.
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