Re: [Mjpeg-users] lav* tools have to be in an avi container?

[er0ck <er...@gm...>]

aha!   right you are!

$> hexdump -C 20071203_205830.mjpeg | head
00000000  2d 2d 6d 79 62 6f 75 6e  64 61 72 79 0d 0a 43 6f
|--myboundary..Co|
00000010  6e 74 65 6e 74 2d 54 79  70 65 3a 20 69 6d 61 67  |ntent-Type:
imag|
00000020  65 2f 6a 70 65 67 0d 0a  43 6f 6e 74 65 6e 74 2d
|e/jpeg..Content-|
00000030  4c 65 6e 67 74 68 3a 20  32 35 38 38 30 31 0d 0a  |Length:
258801..|
00000040  0d 0a ff d8 ff e0 00 10  4a 46 49 46 00 01 01 00
|........JFIF....|
00000050  00 01 00 01 00 00 ff db  00 43 00 05 03 04 04 04
|.........C......|

$>hexdump -C 20071203_205830.mjpeg | grep jpeg
00000020  65 2f 6a 70 65 67 0d 0a  43 6f 6e 74 65 6e 74 2d
|e/jpeg..Content-|
0003f350  20 69 6d 61 67 65 2f 6a  70 65 67 0d 0a 43 6f 6e  |
image/jpeg..Con|
0007e0a0  70 65 3a 20 69 6d 61 67  65 2f 6a 70 65 67 0d 0a  |pe:
image/jpeg..|
000bce50  67 65 2f 6a 70 65 67 0d  0a 43 6f 6e 74 65 6e 74
|ge/jpeg..Content|
000fbd30  65 2f 6a 70 65 67 0d 0a  43 6f 6e 74 65 6e 74 2d
|e/jpeg..Content-|
0013aa30  70 65 3a 20 69 6d 61 67  65 2f 6a 70 65 67 0d 0a  |pe:
image/jpeg..|
001b8550  54 79 70 65 3a 20 69 6d  61 67 65 2f 6a 70 65 67  |Type:
image/jpeg|
001f7180  67 65 2f 6a 70 65 67 0d  0a 43 6f 6e 74 65 6e 74
|ge/jpeg..Content|
002360a0  65 3a 20 69 6d 61 67 65  2f 6a 70 65 67 0d 0a 43  |e:
image/jpeg..C|
00274f40  3a 20 69 6d 61 67 65 2f  6a 70 65 67 0d 0a 43 6f  |:
image/jpeg..Co|
002b3fd0  2f 6a 70 65 67 0d 0a 43  6f 6e 74 65 6e 74 2d 4c
|/jpeg..Content-L|

so it's about 12 frames of jpegs  (one of the "jpeg" must have wrapped over)
so maybe i don't need mjpeg tools?  i just need to split up the individual
jpegs.
if i use "strings" i can grep out 12 jpegs with what looks like
"--myboundary" between them

i had tried putting the mjpeg from the camera into an avi container thusly:
$>mencoder 20071203_205830.mjpeg -o 20071203_205830.avi -ovc copy -of avi
....
Video stream: 51535.333 kbit/s  (6441916 B/s)  size: 3092120 bytes
0.480secs  12 frames


and that worked as far as mplayer was concerned (obviously)
but what is strange is that file (or i guess the avi container) still
thinks  there is an mjpeg encoded file inside:
$> file 20071203_205830.avi
20071203_205830.avi: RIFF (little-endian) data, AVI, 1280 x 1024, 25.00 fps,
video: Motion JPEG

although i don't know what the mjpeg header should look like.

thanks for the reply!
any other help from the list would be appreciated if anyone has ever done
anything like this or if i can do this easily with mjpegtools.
-eric

On Dec 19, 2007 5:00 AM, Burkhard Plaum <pl...@ip...> wrote:

> Hi,
>
> er0ck schrieb:
> > i have what is supposedly a short mjpeg that i downloaded from one of my
> > IP cameras.
> >
> > i want to split up the frames into individual jpgs.   lavtrans gives:
> > $> lavtrans -o image%05d.jpg -f i 20071203_205830.mjpeg
> > Unable to identify file (not a supported format - avi, quicktime).
> > **ERROR: [lavtrans] Error opening 20071203_205830.mjpeg
>
> mjpeg has to be either in AVI or Quicktime.
> Don't know, what yor camera produces, maybe it's just concatenated
> jpeg images. What does
>
> hexdump -C 20071203_205830.mjpeg | head
>
> say?
>
> > Playing 20071203_205830.mjpeg.
> > libavformat file format detected.
>
> Not really helpful message....
>
> Burkhard
>
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