Infoseite // MJPEG artifacts from almost non-compressible



Frage von straubgx:


Hello everybody,

I have a problem with the compression of the MJPG footage of a FujiF10.

Since I originally had before in an international forum to post
I have the problem now sinnigerweise recorded in English, but hope that we are able to understand what problem is.

In the large and full, it is important that I MJPG footage of FujiF10 happy to <2Mbit compress want the whole thing using a MPG4 codecs (DivX/Xvid/ffmpgMP4), or an AVC codec (x264).

Unfortunately, the imagery naturally numerous artifacts to a meaningful Compression difficult or sometimes impossible.

The question is, is there a recommended filter plugin that specializes problem accepting this.

Thanks in advance for all helpful answers.

Gruß, Straubgx


My Fuji F10 digital camera records movies in MJPEG (640x480 30fps) with 9.2 Mbit per second.My problem:
When I encode these MJPEG videos into DivX or XviD with a fixed quantizer of 4 encode some movies with 3-4 Mbits bitrate (in rooms) while others (outdoor movies) take up to 9 Mbits (even with x.264 in distorsion rate settings sq = 22 it does around 7.5 Mbits). So these footage seems nearly uncompressable to a reasonable size.

When I encode from "clean" sources (DVD / DigiTV) with a fixed quantizer of 3 or 4 into MPG4 ASP it results into bitrates of around 1.5 Mbits per second with great quality.

The cause surmised:

From a normal viewing distance the F10's movies look nice rich color and with sufficient detail, but of course this is not a dedicated camcorder s.closer distance and you see lots of noise, so mosquito noise and jpeg artefacts So some artefacts in diagonal lines most probaby resulting from a fast (= bad) downscaling algorithm which scales 30 pics / sec from 6 MP into 640x480.

I think the problem is related to the fact that the MJPG artefacts are different in any frame hence the codec finds a lot of differences in the frames - it needs lots of bits to spend.

I could surely smoother the picture but do not want to loose any details in the movie, which is what any smoother that I did threw s.this footage.

The normal I can reduce noise with ffdshows "denoise3d" in HQ mode achieving good results, but to get rid of mosquito artefacts I tried the AviSynth msmooth.dll and also I did try the "vague DENOISER" with no improvent for msooth and visible blur for the vague DENOISER so can not use them here.

3D convolution give no improvement. Deringing / deblocking even on 200% gives no improvemen either. I tried convolution3d, MSU DENOISER, mplayer DENOISER temporal and all the - otherwise great - build stuff into ffdshow to no avail, I either get loose details or huge files.

Are my MJPGs "uncompressble" without the unwanted of loosing detail or is there a dedicated software that can clean up MJPEG footage so it can properly encode into MPG4 or AVC?

Space


Antwort von TheBubble:

Let the compressor instead of a fixed Quantisierungseinstellung these rules, so it your data request nährungsweise achieved. Or even increases, the coefficients of Quantisierungsmatrix.

The application of filters for the suppression of noise besides the noise synonymous ever actually wanted to remove image details. If you as a result of too many artifacts interfere, try it before compression with a slight blur. Here the focus is back, but perhaps do you like the result better.

If you block artifacts disturb, for example, then search for "deblocking filter."

Space


Antwort von straubgx:

Let the compressor instead of a fixed Quantisierungseinstellung these rules, so it your data request nährungsweise achieved. Or even increases, the coefficients of Quantisierungsmatrix.

The application of filters for the suppression of noise besides the noise synonymous ever actually wanted to remove image details. If you as a result of too many artifacts interfere, try it before compression with a slight blur. Here the focus is back, but perhaps do you like the result better.

If you block artifacts disturb, for example, then search for "deblocking filter."

Thanks for the help, but unfortunately not.

If I have a fixed bitrate RESTRICT, eg 2 Mbit MPG4 is the whole picture washy, too many differences between the images for 2Mbit ..

I must somehow the material of the artifacts cleaned MJPG get a Blur is synonymous unfortunately no solution takes away details.

Block artifacts exist in MJPG not.

Space


Antwort von TheBubble:

"straubgx" wrote:
If I have a fixed bitrate RESTRICT, eg 2 Mbit MPG4 is the whole picture washy, too many differences between the images for 2Mbit ..

Are the recordings with the help of a tripod or from the hand made? If with a Tripod: it Szenzen containing many moving objects, or they change in the Lighting?

If many changes between the individual images are available only as few as possible and details may be lost, the data rate must be increased until the demands are met.

"straubgx" wrote:
I must somehow the material of the artifacts cleaned MJPG get a Blur is synonymous unfortunately no solution takes away details.

Artifacts can not simply take away, synonymous with no other image details to lose. How is an automatic correction filter to decide whether the "point cloud" is an artifact or whether grade point s.diese many dust particles were filmed?

"straubgx" wrote:
Block artifacts exist in MJPG not.

But, it's synonymous with a JPEG compression.

Space


Antwort von Daigoro:

"straubgx" wrote: When I encode from "clean" sources (DVD / DigiTV) with a fixed quantizer of 3 or 4 into MPG4 ASP it results into bitrates of around 1.5 Mbits per second with great quality.
"Clean" source of DVD sounds strange for me because of the MPG2 compression?
Rauscht the original material, perhaps a bit much? (The Fuji is not a video camera s.sich ...)
1.5 Mbit / s and "great quality" synonymous (in full PAL resolution? Ne For such low data rate, I must mostly down on 320x240/25fps artifact in order not to storm versumpfen)

Is there somewhere's example videos?

Space


Antwort von straubgx:

Hi, sorry there are of course already blocks MJPG in the data when I start very deep, I was in the F10, there is not, as it travels 9.2Mbit, but a lot of noise and Grisseln, if you look closer, but is probably normal with a photo camera in video mode.

And with the "clean" DVD material, I meant that as little noise and is synonymous not so restless grisselige images. Yes, blocks formation sometimes seen in still images of Purchase DVDs but it would not be a problem would lead to a yes no compression in MPG4 letting.

So, 1.5 Mbps in MPG4 I have always been perfect for the safety copy of a DVD MPG2, no artifact thunderstorms in full PAL ResolutionPSNR about 43dB, fixed Q = 3, my, you might MPG2 1.5 Mbit?

Yes to me, this material is included with a FujiF10, a very nice little camera which I find synonymous quite usable video mode, makes at least 640x480 with 30fps. Look for synonymous camera nice situation, it is only very modest compression.

Therefore I thought there was perhaps a specialized plugin that is genu accepting these artefacts, there so many besimmt your video camera and want runterkomprimieren times on the photos to the archive ...

Space





slashCAM nutzt Cookies zur Optimierung des Angebots, auch Cookies Dritter. Die Speicherung von Cookies kann in den Browsereinstellungen unterbunden werden. Mehr Informationen erhalten Sie in unserer Datenschutzerklärung. Mehr Infos Verstanden!
RSS Suche YouTube Facebook Twitter slashCAM-Slash