avconv: convert .avi to different codec

[Feathers McGraw]

Hello again...

I have some .avi files with a codec that is unsupported by RaspBMC, so I'd like to re-encode them.

The unsupported codec is "MS MPEG-4 Video v3 (DIV3)" and I'd like to use "libx264".

I've had a go at converting one of the files but I've been having some problems. Here's the output:

feathers-mcgraw@62-West-Wallaby-Street:/data/Videos/South Park/South Park - Season 01 - (1997 - 1998)$ avconv -i INPUT.avi -vcodec libx264 OUTPUT.avi
avconv version 0.8.6-6:0.8.6-1ubuntu2, Copyright (c) 2000-2013 the Libav developers
  built on Mar 30 2013 22:20:06 with gcc 4.7.2
Input #0, avi, from 'INPUT':
  Duration: 00:24:08.78, start: 0.000000, bitrate: 868 kb/s
    Stream #0.0: Video: msmpeg4, yuv420p, 464x352, 23.98 tbr, 23.98 tbn, 23.98 tbc
    Stream #0.1: Audio: mp3, 48000 Hz, stereo, s16, 128 kb/s
[buffer @ 0x20fea00] w:464 h:352 pixfmt:yuv420p                                               
Incompatible sample format 's16' for codec 'ac3', auto-selecting format 'flt'                 
[libx264 @ 0x2113120] using cpu capabilities: MMX2 SSE2Fast FastShuffle SSEMisalign LZCNT     
[libx264 @ 0x2113120] profile Main, level 2.1                                                 
[ac3 @ 0x21138e0] invalid bit rate
Output #0, avi, to 'S01E01.avi':
    Stream #0.0: Video: libx264, yuv420p, 464x352, q=-1--1, 90k tbn, 23.98 tbc
    Stream #0.1: Audio: ac3, 48000 Hz, stereo, flt, 200 kb/s
Stream mapping:
  Stream #0:0 -> #0:0 (msmpeg4 -> libx264)
  Stream #0:1 -> #0:1 (mp3 -> ac3)
Error while opening encoder for output stream #0:1 - maybe incorrect parameters such as bit_rate, rate, width or height

I'm out of my depth here, any help would be fantastic.

Thanks,

Feathers

[Rog132]

Searching with the 'avconv conversion mp3 -> ac3 Error while opening encoder '

A hit: avconv giving error on audio stream - http://superuser.com/questions/42697...n-audio-stream


Testing at here - the ac3 codec seems to need more information - with the

avconv -i Test.wmv -c:a ac3 Test.avi

There is an error:

Stream #0:0 -> #0:1 (wmav2 -> ac3)
Error while opening encoder for output stream #0:1 - maybe incorrect parameters such as bit_rate, rate, width or height

With the bit rate:

avconv -i Test.wmv -c:a ac3 -b:a 448000 Test.avi

no problems

More: http://libav.org/avconv.html#toc-Codec-AVOptions

---------EDIT---------

Should be '-b:a 48000'

[Feathers McGraw]

Thanks for that! How do I choose a bit rate?

I guess setting it above a certain value will be a waste, as the original encoder will have lost some info?

Feathers

[Rog132]

Bitrate

You pick the bitrate so that it satisfies your needs. With the video you don't see artifacts and with the audio it sounds good.

Higher bitrates are usually easier on the low end systems.

If you are squeezing files to the limited space then there are calculators to estimate the space consumption.

As example the Avidemux calculator:

[Feathers McGraw]

Ok thanks!

I've written a little BASH script to convert the files because there are so many of them. I'll post it here just in case it's useful to someone:

#!/bin/bash

if [ $# -ne 2 ]; then
echo "Usage: $0 source target"
exit
fi

SOURCE_DIR=$1
TARGET_DIR=$2
IFS=''

for file in $SOURCE_DIR/*.AVI $SOURCE_DIR/*.avi
do
echo "infile: $file"
out_file=$TARGET_DIR/"${file##*/}"
out_file="${out_file%.*}".avi
echo "outfile: $out_file"
avconv -i "$file" -vcodec libx264 -c:a ac3 -b:a 48000 "$out_file"
done

The script works for me, but if can see a better way to write it I'd be interested in learning how and why!

Feathers

[GreyGeek]

Ok thanks!

I've written a little BASH script to convert the files because there are so many of them. I'll post it here just in case it's useful to someone:

.....
avconv -i "$file" -vcodec libx264 -c:a ac3 -b:a 448000 "$out_file"
...

The script works for me, but if can see a better way to write it I'd be interested in learning how and why!

Feathers

You say it works for you, but shouldn't "-b:a 448000" be "-b:a 44800" Nearly half a million bit rate seems high. Is Avconf defaulting to another bit rate?

BTW, thanks for that script. It is a classic example of how software is written and improved upon in the open or GPL environment. In other environments a person is tempted to take the input from others, add it to their code (if not outright steal the code), compile and/or obfuscate it, then copyright it and sell it. After that, no one benefits except the thief.

[Feathers McGraw]

Ha!

How on earth did you spot that? Keen eye you have there, thanks a lot!

I'll change the script and edit the original post. Maybe it'll encode faster now!

Feathers

[GreyGeek]

Can you find the "n"
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mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm mmmm
mmmmmmmmmmmmm

[kubicle]

Can you find the "n"
mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm mmm
mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm mmm
mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm mmm
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mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm mmmm
mmmmmmmmmmmmm

The length of the strings is a bit of a give away.

[Feathers McGraw]

The length of the strings is a bit of a give away.

Even knowing that, I can't see it - it's making my eyes go funny!

[vinnywright]

can you find the "n"
mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm mmm
mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm mmm
mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm mmm
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mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm mmmm
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;d

vinny

[Feathers McGraw]

Congrats, you win!!

[GreyGeek]

How about now?

mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm mmm
mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm mmm
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Kubical, the length of the line sure shortens the search!