[FFmpeg-user] (no subject)

[Anne at Picaflor Azul]

Hello,

   This is my first time using an email list, so please let me know if I
am doing
anything wrong.

   I have been trying to record my desktop and make it into a good quality
dvd.
This is what I have done so far.

avconv -f x11grab -s hd1080 -r 30 -i 0:0 -acodec pcm_s16le -vcodec libx264
-preset
 ultrafast -crf 0 -threads 0 -f alsa -ac 2 -i pulse recording-filename.mkv

avconv -i recording-filename.mkv recording-filename.vob

This looks a lot better than anything else I have been able to figure out,
but
the video quality seems to be a little less than I would like. It might do
though,
I think it is very close. I have not yet checked the file size that this
produces.

I have been trying to figure out how to do a two pass encoding. This seems
to work:

avconv -i recording-filename.mkv -c:v mpeg2video -pass 1 -an -f rawvideo
-y /dev/null

but I havent gotten any second pass command to work yet. This one:

avconv -i recording-filename.mkv -pass 2 -b 3000k -s 720x480 -r 29.97
 recording-filename2pass.vob

gives the following output:

avconv version 0.8.3-4:0.8.3-0ubuntu0.12.04.1, Copyright (c) 2000-2012 the
Libav developers
  built on Jun 12 2012 16:52:09 with gcc 4.6.3
[matroska,webm @ 0x19049a0] Estimating duration from bitrate, this may be
inaccurate
Input #0, matroska,webm, from 'recording-filename.mkv':
  Metadata:
    ENCODER         : Lavf53.21.0
  Duration: 00:05:09.50, start: 0.000000, bitrate: N/A
    Stream #0.0: Video: h264 (Main), yuv420p, 1920x1080, PAR 1:1 DAR 16:9,
30 fps, 30 tbr,
 1k tbn, 60 tbc (default)
    Stream #0.1: Audio: vorbis, 48000 Hz, stereo, s16 (default)
File 'recording-filename2pass.vob' already exists. Overwrite ? [y/N] y
[buffer @ 0x1cd3860] w:1920 h:1080 pixfmt:yuv420p
[scale @ 0x1df1da0] w:1920 h:1080 fmt:yuv420p -> w:720 h:480 fmt:yuv420p
flags:0x4
[mp2 @ 0x1945460] bitrate 3000 is not allowed in mp2
Output #0, svcd, to 'recording-filename2pass.vob':
  Metadata:
    ENCODER         : Lavf53.21.0
    Stream #0.0: Video: mpeg2video, yuv420p, 720x480 [PAR 32:27 DAR 16:9],
q=2-31, pass 2,
 3000 kb/s, 90k tbn, 29.97 tbc (default)
    Stream #0.1: Audio: mp2, 48000 Hz, stereo, s16, 3000 kb/s (default)
Stream mapping:
  Stream #0:0 -> #0:0 (h264 -> mpeg2video)
  Stream #0:1 -> #0:1 (vorbis -> mp2)
Error while opening encoder for output stream #0:1 - maybe incorrect
parameters such as
 bit_rate, rate, width or height


This one:

avconv -i recording-filename.mkv -an -pass 2 -b 3000k -s 720x480 -r 29.97
recording-filename2pass.vob

gives this:

avconv version 0.8.3-4:0.8.3-0ubuntu0.12.04.1, Copyright (c) 2000-2012 the
Libav developers
  built on Jun 12 2012 16:52:09 with gcc 4.6.3
[matroska,webm @ 0x14b89a0] Estimating duration from bitrate, this may be
inaccurate
Input #0, matroska,webm, from 'recording-filename.mkv':
  Metadata:
    ENCODER         : Lavf53.21.0
  Duration: 00:05:09.50, start: 0.000000, bitrate: N/A
    Stream #0.0: Video: h264 (Main), yuv420p, 1920x1080, PAR 1:1 DAR 16:9,
30 fps, 30 tbr, 1k tbn,
 60 tbc (default)
    Stream #0.1: Audio: vorbis, 48000 Hz, stereo, s16 (default)
File 'recording-filename2pass.vob' already exists. Overwrite ? [y/N] y
[buffer @ 0x1887860] w:1920 h:1080 pixfmt:yuv420p
[scale @ 0x19a5da0] w:1920 h:1080 fmt:yuv420p -> w:720 h:480 fmt:yuv420p
flags:0x4
[svcd @ 0x14f5080] VBV buffer size not set, muxing may fail
Output #0, svcd, to 'recording-filename2pass.vob':
  Metadata:
    encoder         : Lavf53.21.0
    Stream #0.0: Video: mpeg2video, yuv420p, 720x480 [PAR 32:27 DAR 16:9],
q=2-31, pass 2,
 3000 kb/s, 90k tbn, 29.97 tbc (default)
Stream mapping:
  Stream #0:0 -> #0:0 (h264 -> mpeg2video)
Press ctrl-c to stop encoding
avconv:
/build/gpocentek-libav-extra_0.8.3ubuntu0.12.04.1+medibuntu1-amd64-0rSAlL/libav-extra-
0.8.3ubuntu0.12.04.1+medibuntu1/libav/libavcodec/ratecontrol.c:693:
ff_rate_estimate_qscale:
 Assertion `picture_number<rcc->num_entries' failed.
Aborted (core dumped)

I would like to know if I am making any mistakes so far, especially ones
that will eventually
force me to start all over again.
Can you give me a pass two command that will work?
What parameters will it be profitable to play with when I am balancing
video quality
and file size?
Are there any other techniques I should consider using to optimize quality
and file size?

Thanks in advance,

Anne
www.picaflor-azul.com