[FFmpeg-user] H.264 to jpeg thumbnail

Henk D. Schoneveld belcampo at zonnet.nl
Wed Sep 9 17:09:39 CEST 2015

On 09 Sep 2015, at 16:40, Moritz Barsnick <barsnick at gmx.net> wrote:

> On Wed, Sep 09, 2015 at 15:48:29 +0200, Henk D. Schoneveld wrote:
>> Could you post the mentioned jpg's ?
>> Watched them on OSX but don't see the things you're describing, maybe I don't understand what you mean.
> Process the input with
> $ ffmpeg -i clock.ts -t 2 clock.%04d.jpg
> and compare 0056.jpg, 0057.jpg and 0058.jpg. The second hand should be
> progressing, but it doesn't... Actually, 0056 and 0058 look identical,
> and 0057 looks backward in time (and as if it had interlace artefacts).
With my slightly older version of ffmpeg 2.6 I don’t see what you mention.
Source is 30fps BTW between start of 56 57 and end of 58, is 3/30 of a second, so no progress seems OK to me. Also I don’t see ‘interlace-like’ artefacts. The 60 one shows something like interlace on the bottom half of the second hand, 61 is OK again. Unless you watch these stills, one frame duration is 0.03 sec, so you won’t notice. At least I can’t see it in QTplayer.
But I do see it with VLC.
> I only had a short look at PTS and DTS in the source file, but couldn't
> make sense of it.
> I claim that this "problem" exists in the source file. Unless VLC and
> mplayer have a demuxing problem common with ffmpeg.
> Moritz
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