Lair Of The Multimedia Guru

October 31, 2007

FFmpeg weekly news #2

After the extreemly popular recent changes in ffmpeg blog post, here are the next news, precissely 1 well something ;) afterwards

Note, errors and ommissions are unintended and if you spot any tell me and ill fix them (except spelling and grammer i wont bother fixing these)

  • More work and patches by ronald and luca to get the IPv6 related code closer to being functional
  • diego removed Metrowerks Codewarrior support due to it being unmaintained, broken and making the code more ugly (also not a single person complained so there is likely no one using it)
  • Altivec runtime detection fix/cleanup and messup
  • The remaining H.264 PAFF patches from jeff downs hit svn, sadly this also caused a slowdown of the decoder, so this needs more work to prevent this slowdown
  • reimar removed the extreemly broken SIGILL based cpu extension detection code, the SIGILL code should have never been commited in the first place …
  • luca barbato added support for a user specifyable maximum number of frames per RTP packet
  • a optimized VP3 IDCT for blackfin by marc hoffman
  • mans changed configure to use pr instead of cat -n as later is not standard, this will likely cause some minor annoyance to some users of non standard systems well fix your system, dont expect every lib and application to workaround it!
  • a DNxHD (SMPTE VC-3) encoder by baptiste
  • DNxHD 10 bit depth and 36mbit decoding support by baptiste
  • user specifyable zlib compression level for PNG by reimar
  • ogg seeking simplification and bugfix by reimar
  • a very small part of the MMS patch hit svn
  • some minor h.264 optimization by jeff downs
  • infinite loop and negtive memcpy in the ac3 and aac parser fix by myself
  • RC4, DES and encrypted asf support by reimar
  • VP6 with huffman encoded blocks support by aurel
  • deblocking for H.264 PAFF fix by Martin Zlomek
  • nellymoser ASAO decoder by a840bda5870ba11f19698ff6eb9581dfb0f95fa5, 539459aeb7d425140b62a3ec7dbf6dc8e408a306, 520e17cd55896441042b14df2566a6eb610ed444
    Loic Minier and Benjamin Larsson
  • support for electronic arts demuxer and decoders by aurel and peter ross
  • speling, gramer and warning fixed by diego
  • streaming to XBox360 fix by patric stout
  • a regression fix related to url_split() by ronald
  • display and sample aspect ratios display by michel
  • WMV3 FASTTX=0 fix by kostya
  • AVProgram API to export mpeg ts program information to the user app by nico
  • rm demuxer changed to output frames instead of slices by kostya and roberto, this simplifies alot of related code
  • Beam Software SIFF demuxer and video decoder by kostya
  • support for reading duration from Xing and VBRI tag in mp3 files by andreas
  • more flac encoding optimizations by loren
  • moving the framecrc muxer to its own file by aurel
  • and theres a patch for a MLP/TrueHD decoder by Ian Caulfield on ffmpeg-dev which i should review
  • many other things ive missed …
Filed under: FFmpeg — Michael @ 0:34

October 6, 2007

F50fd part2

The image stabilization, well ive done more testing, 10 images without IS, 10 at continous mode, 10 at shot only mode, all at the wide angle side at 1/4 sec 12mp, quick summary the IS does not help, find the 2 best looking croped images for each of the 3 cases in the table below:

IS:off
IS:continous
IS:shot only

Random low iso images








and in case anyone is wondering how i reached a image number of above 6000 in a few days testing, well thats what happens if you switch sd cards around randomly one thing i learned from that though was the FD50fd had no problems displaying images made with the IXUS though it did not play my naively made mjpeg in AVI :( it did not even play its own video after it was remuxed but i didnt investigate this any further …

Filed under: Cameras,Pictures — Michael @ 22:32

Fujifilm F50fd vs. Canon digital ixus 30

I wanted a small compact digicam which is better at taking pictures in bad light than my ixus30, has full manual controls, a wider angle lens, … well no such camera exists currently. So i decided to try the F50fd, it has aperture and shutter priority modes, can take images at up to ISO 6400 and has a image stabilizer.

Size and weight: Well its a bit bigger and heavier than my ixus30 but it still is small enough to fit in my pocket

The image stabilizer: Well, what can i say, i took many images at the telezoom side at 1/5sec shutter with it in continous mode, with it in shot only mode and with it disabled, no single image was useable. Repeating the test at the wide angle side of the zoom at 1/5sec some images where ok others where not, the stabilizer again didnt make much of a difference, sadly ive lost patience and didnt take more than about 5 images each with stabi in mode 1 in mode 2 and without stabi so i dont have statistically significant data for that part. What i can say though is that the stabi did not help me take a single useable image at a shutter speed at which i wouldnt be able to take a good one with a few tries without the stabi

The manual control: Well it does work, and even quite well, you can change the aperture with a single button press, the exposure correcton as well can be changed with a single button press (after you switched the buttons into the right mode which needs 1 button press). Very sadly to change the ISO you have to press at least 3 buttons (4 after the camera is turned on). On the ixus30 you need 1 button press to cange ISO and exposure correction if you are in the correct menu (yes you can take images without leaving the menu on the ixus this doesnt work with the f50 ISO menu), you need 2 button presses to change between the ISO and exposure menues and 2 to reach the exposure and 4 for the ISO menu after power on on the ixus, so in summary the manual control could be made available more directly on both cameras.

Arbitrary limitations: There where a few surprises for me as i was playing around with the camera, first the aperture priority mode is limited to a shutter of 1/4sec at the long side, the shutter priority mode though can be used with up to 1sec. Longer exposures (up to 8 sec) are possible but only at ISO 100

Deleting images: I was mildly annoyed that i had to press 3 buttons to delete an image, but what was much more annoying was that the deletion comes with a nice animaton which you cant disable and which you have to let finish before you can do anything else. That is, its not hard to press the 3 button sequence a few times while the animation plays sadly it has no effect

Auto focus: This one does work better than on the ixus in low light with the focus assist lamp disabled

High ISO image quality: Well i hoped that the F50 would be a lot better at taking images at high ISO, sadly the difference is not that large, but see yourself:
F50 ISO3200 1/4sec f/2.8 Now how does one compare this to the IXUS30 which just has ISO400 well one (mis)uses the exposure correction to get the exposure one wants and then fixes the brightness/contrast in software
IXUS30 ISO400 -2EV 1/5sec f/2.8 (way too dark yes)
after -vf ow=7:8:16 and gimp to fix levels So which looks better? teh F50 one of course, lets compare it to a longer exposure of the IXUS
ISO400 -1EV 1/2sec f/2.8
fixed up levels in gimp
and with -vf ow=7:8:16 With the 2x longer exposure i would say the IXUS is at least as good as the F50 (with the shorter exposure). And there would be thumbnail images if wordpress would generate them or i knew how to upload several images at once instead of each one individually …

ISO values: well the more i played with the F50 the more i noticed that its ISO values dont match the IXUS ones, that is the IXUS30 at ISO400 seems to match approximately ISO600 on the F50 (matching here means same shutter, aperture and equally bright final images)

Colors: well the F50 is about as (in)accurate as the IXUS30 though they are different

Will i keep the F50? Probably not the improvement is too small over the IXUS30 also i dont like the heavy noise reduction the camera does, it becomes noticeable already at ISO400, the IXUS30 doesnt do this though more recent IXUS versions seem to also follow the trend of butchering images with noise reduction

Ill upload more pictures tommorow …

Filed under: Cameras,Pictures — Michael @ 3:44

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