[FFmpeg-user] Probing jpg, png and tiff images without decoding frames

Robert Krüger krueger at lesspain.de
Thu Aug 8 10:04:28 CEST 2013


On Wed, Aug 7, 2013 at 5:22 PM, Stefano Sabatini <stefasab at gmail.com> wrote:
> On date Tuesday 2013-08-06 13:09:00 +0200, Robert Krüger wrote:
>> Hi,
>>
>> it seems the ffmpeg always decodes the listed types of images to
>> determine their properties. What I did to check this, was to run
>> ffmpeg -i <imagefile> as well as ffprobe -show_streams <imagefile>
>> with each of these formats and set a breakpoint in
>> avcodec_decode_video2.
>>
>> This is not a problem in many cases, however when using ffmpeg,
>> ffprobe or its libraries to extract metadata such as codec, size and
>> pixel format from thousands of image files (imagine analyzing a full
>> SD card of Hires JPG images), the difference between header parsing
>> and decoding becomes very significant (especially with large images
>> for obvious reasons).
>>
>
>> Is this (extracting metadata for those formats just by header parsing)
>> currently implemented and I am just missing a command line argument?
>>
>> If not, shall I submit this as an enhancement request in trac?
>
> Makes sense, possibly mentioning this thread or a short summary.

OK, I did (https://trac.ffmpeg.org/ticket/2845). I hope the
description is sufficient.


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