Frage von OnkelAngelika:
Hi folks,
I'm looking for an easy option, key images, or more generally still pictures from AVCHD streams to extract. The claim is that these pictures remain unchanged ( "s.is"), without post effects / filters ÓÄ artifact. come from the stream.
Background of all this is that HD cameras using the standard test charts together with the IMAT software to test. I'm not sure that, for example, VLC snapshot function is sufficient - or maybe? What is a solution for the corresponding "raw" does, or an alternative route?
About suggestions I would be grateful.
Antwort von WoWu:
I fear, then you compare apples with pears.
IMAT compares image quality of photos.
When AVC is but a moving process in which only the decoder for image modification tools to use.
Isolated you do a frame from the stream, makes little sense, since it is not the processing has completed.
There are of course still very specific tools, such as that the procedure allows it to slice level, ie synonymous only parts of the interlaced image and other parts progressive encoding. So how should those elements that just when the movement effect, with a photograph is to compare them.
Moreover, synonymous, of course, the question of which AVC (HD) stream as raw material to be applied, because the manufacturers of a wide choice s.Tools and Profiles are available and each manufacturer's Stream along its potential uses ... with the success that the results can show extreme differences.
There is a widespread misconception that modern coding still function as MJPEG .... just as there are
no images arranged together, in the sum of a movie shown.
Consequently, the synonymous repeatedly published stills modern coding only conditionally meaningful.
Antwort von OnkelAngelika:
Good, I understand the problem of variable Dekodierergebnisse - exactly where my problem lies.
My question in precise form, therefore, is how should I make the HD camcorder images "raw", so that I am with IMAT color, SNR, Resolution fairs can be real - all parameters, which ultimately of course synonymous with the image processor of the device and therefore will be influenced with in the analysis.
Will there really only frames from the live component / HDMI signal to extract - which is probably s.ehesten the "Still Image" would? I think it would have other opportunities to provide reliable quality measurements can be made.
Antwort von WoWu:
That what you get saved as a picture is not comparable with the content, such as a JPEG.
An example that illustrates this:
AVC provides a tool, the
film grain modeling heist. (currently of the most common, rudimentary AVCHD Codces not yet supported)
This tool analyzes the recorded material Graining and establishes the underlying solid model. Afterwards the model s.den decoder and the grain transferred from the material removed. The resulting "adjusted" picture is stored or transmitted. The decoder is based on the present (one-time transfer model) the grain re-calculated and the Picture again added. Meaning is clear, I hope.
The grain can be somewhat synonymous from the sensor chip to ... must not always film.
So now you take a saved picture, it is not a grain to be found. However, Koren practices among others in his image distortion or charpening measure, the values are not comparable.
This should now only an example for many other methods to be used in such procedures are used and the content of the result can be totally different.
The IMAT technique is not seriously on such transfer procedures and results of direct attack.
If you select the HDMI path, should be synonymous all images compared to the same way, because of course the Wandungseffekte of the Tx and the sink, which brings with HDMI, not only in a proceeding may reflect.
