[FFmpeg-user] With mxg/MxPEG, keyframes only are seen?

[Jesse Gordon]

On 11/01/2012 09:35 AM, Carl Eugen Hoyos wrote:
> Jesse Gordon<tojesseg<at>  gmail.com>  writes:
>
>> ffmpeg -f mxg -i M00001.jpg foo-%03d.jpeg
> You need -vsync 0 to force ffmpeg not to drop frames
> to keep (too low) constant frame rate.
>
> $ ffmpeg -vsync 0 -f mxg -i M00001.jpg foo-%03d.jpeg
>

I tried that, and it quickly produced 3 jpeg files with the same sizes 
as the first 3 before:
-rwx------ 1 root root   96185 Nov  1 09:49 foo-001.jpeg
-rwx------ 1 root root   96202 Nov  1 09:49 foo-002.jpeg
-rwx------ 1 root root  119517 Nov  1 09:49 foo-003.jpeg

but then ffmpeg hangs/stalls with this message:

ffmpeg -vsync 0 -f mxg -i M00001.jpg foo-%03d.jpeg
[mxg @ 0x8ec7520] Estimating duration from bitrate, this may be inaccurate
Guessed Channel Layout for  Input Stream #0.1 : mono
Input #0, mxg, from 'M00001.jpg':
   Duration: 00:02:56.85, start: 1351625054.845054, bitrate: 63 kb/s
     Stream #0:0: Video: mxpeg, yuvj420p, 1280x960, 1.83 tbr, 1000k tbn, 
1000k tbc
     Stream #0:1: Audio: pcm_alaw, 8000 Hz, mono, s16, 64 kb/s
Output #0, image2, to 'foo-%03d.jpeg':
   Metadata:
     encoder         : Lavf54.35.100
     Stream #0:0: Video: mjpeg, yuvj420p, 1280x960, q=2-31, 200 kb/s, 
90k tbn, 1.83 tbc
Stream mapping:
   Stream #0:0 -> #0:0 (mxpeg -> mjpeg)
Press [q] to stop, [?] for help
[mjpeg @ 0x8ee6880] Error, Invalid timestamp=1, last=1
     Last message repeated 1 times

In this state, ffmpeg is not using much CPU or memory. I let it sit like 
this for several minutes and nothing happened.
(Without -vsync 0, it takes about 3 seconds to produce the 21 frames and 
happily exit.)

When it is hung like this, pressing q or ? or spacebar has no effect.
Pressing control C just produces a newline, but if I press ^C a few 
times then it exits with the message "Received signal 2: terminating."

My video source file is here:
http://bookcracker.com/M00001.jpg
(md5sum 79a15f8c5a6a08a62fc542741f8b22ea)

Can you please check to see if you get the same hung ffmpeg as I?

Thank you very much,

Jesse Gordon


> Carl Eugen
>
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