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720p 60p GH2 hack: an attempt to improve the quality, stability and reliability.
  • I am trying to improve the quality of 720p 60p in GH2.

    I did some research in the forum about PTools settings but I did not find the answers I need...

    What happens is:

    Only GOP which works good for 720p 60p are GOP 30 and GOP 3, all other GOP gives diagonal pattern (rain) in computer monitor. But the GOP 3 in 720p always stops recording and it seems the card is not the problem, I am using Sandisk 45mbps and other people says the Sandisk 95mbps also stops recording in 720p hacks... The GOP 6, 12 and 15 works for some shoots, but they are unstable (sometimes stops recording) and gives diagonal pattern (rain) in computer monitor. GOP 3 stops recording all the time, no matter the bitrate (I tested GOP 3 from 40 to 200mbps). So GOP 30 is the only option.

    Problem is: when using the GOP 30 the camera encoder always keeps the bitrate very low when the camera is quiet, when there is no motion in the image, and this gives lots of macroblocking and texture lost in low light. Even when I set the bitrate to 48mbps or 64mbps in PTools the camera does not record 48mbps or 64mbps, StreamParser shows only around 23mbps... (for static low light shoots)

    The auto quantizer all to motion or all to details did not make any difference. So I did some try to change settings in TESTER options of PTools. I fount the TOP and BOTTOM bitrate limits and I enabled it with 48000 and 42000 for top and bottom 720p, but this makes no effects in encoding, bitrate is still very low for static shots no matter the bitrate I type in PTools...

    Only thing I found to make the bitrate encoding keep high is the GOP 3, but camera stops recording in all 720p shoots, the GOP 3 just works for 1080p.

    So I am wondering if there is a way to keep the bitrate high using GOP 30 in 720p...

    Any suggestion welcome, thanks.

  • 36 Replies sorted by
  • AFAIR this "rain" symptom is not at all the camera's fault, but a mis-interpretation of the H.264 encoded video by some playback software. Try replaying your raw .MTS files with a different software (e.g. a recent VLC) and see whether the symptom doesn't vanish.

  • thanks for the tip.

    also I found a tip here in pv to transcode the original mts file using 5dtorgb and it seems to solve the problem, after conversion I did not see the diagonal pattern (rain) problem anymore, needs more plays to trust the solution.

    so now I can try to improve the GOP 6 for 720p...

  • So these are the new tests for 720p 60p

    GOP 6 camera frezzes sometimes, recording stops sometimes, no matter the bitrate.

    GOP 12 was stable in the first tests, but macroblocking starts to show in the shadows and there are texture lost in dark scenes, frame rate seems to become different, lower, in dark regions. Not pleasant to the eye.

    GOP 8 seems to be the sweet spot, no significant macroblock in dark scenes, no significant texture lost, stable in first tests, needs more tests. Only issue I found in 3200 iso is near the objects edges the noise is more fine grain and in flat surfaces noise is more gross, but it is not anoying, not disturbing, and cleans ok with neatvideo, it is gone after denoise. In 3200 iso the texture is more fine near the I frames and more gross near the P frames, but this also goes away after denoise. (just I and P frames in GOP 8).

    GOP 6 would be better, but I could not find a way to make it work, so GOP 8 is the best solution. I have the Sandisk 32GB SDHC 45MBps, I would like to try GOP 6 with the Sandisk 95MBps card... but for now I will do more tests with GOP 8.

    5dtoRGB works ok for transcoding and I did not see diagonal pattern (rain) yet after transcoding.

    I was thinking I would need to keep GOP number to close in each second, 60 frames have 10 GOP6, 5 GOP12, but there is 7,5 GOP8 inside a second of 60p, but this is no problem yet in the first tests.

    SH was set to 128Mbps, H was set to 64Mbps, both worked ok until now.

    It seems GOP 8 will be ok for 720p 60p, needs more tests... in different light situations, different objects textures and different motions, camera motion and objects motion...

  • As @karl pointed out, the diagonal rain effect is not burned into the recording. It is due to a flaw in the MainConcept H.264 decoder, which is bundled with Adobe CS6 and CC.

    I experimented with 720p GOP-3 patches in early unreleased versions of Flow Motion v2. It performed much like the 720p GOP-6 patch in FM 2.02, but GOP-3 was not quite as stable as GOP-6 at 100Mbps. Due to shared patch settings between HBR 1080p and 720p video modes, it was very difficult to achieve reliability at high bitrates in all modes simultaneously.

    Due to the way the H.264 encoder alternates between B-frames and I/P frames, IBP GOP-length must be evenly divisible by 3. A GOP-8 patch would only work properly with B-frames disabled, but that would require a higher bitrate to maintain the same quality level. If you're looking to optimize 720p modes without concern for HBR mode, I'd suggest starting with the FM2 720p GOP-6 settings, and alter it to work in GOP-3 mode.

  • I went through all this a long time ago. There's no need to re-invent the wheel. Check out the 720 60P in Sanity 5.1. The dirty work has already been done.

  • @LPowell @Ralph_B many thanks! I got the set ini files of FM202 setf and S51 seta

    I found something in the FM202 ini file which can be wrong (the top is lower than the bottom):

    1080p24 Low Top Setting=52500

    1080p24 Low Bottom Setting=55000

    Also the 24L bitrate is 32500000 so maybe the top would be 32500 and botom 25000 ???

    I have two questions:

    can I update firmware to change from FM202 to S51 and from S51 to FM202 ?

    can I go back to panasonic original version 1.1 ?

  • I loaded FM2.02 to the camera and did initial tests. It was stoping recording in SH and H so I did some changes and now it is working stable for me with amazing quality for 720p in low light and sun light. I tweaked the Flow Motion 2.02 to make it more stable in 720p 60p recording in my Sandisk 32GB SDHC 45Mbps card, no more stop recording until now, needs more tests. Texture is homogeneous and no macroblocking. I tweaked the 1080p 24p also. If you want to try it:

    fm202_gop3_gop9.zip
    9K
  • Thanks @LPowell

    Flow Motion is amazing quality for both 720p and 1080p !!!

    I did more tests and it is stable with the tweaks I did.

    Great work!

  • @apefos Thanks for taking a detailed look at FM2 and providing your modified settings for review. I'm busy with a project deadline this week, but will try to find time to test and compare your revisions with FM 2.02. A few initial observations:

    • 1080p24 Low Top Setting & 1080p24 Low Bottom Setting - these FM2 settings are correct, they are involved in optimizing FM2's 24L 4GB file-spanning reliability at 60Mbps. Your boosted Video Bitrate 24L setting will probably have an adverse effect on this.

    • Video Bitrate 24H & 1080p24 Frame Limit - Boosting these higher than FM2 settings may provoke reliability issues with 140Mbps Turbo mode and 30Mbps SD cards. If this is what required an Initial Quantizer setting of 18 in your revision, I'd consider that an undesirable compromise.

    • 720p GOP Size 9 - FM2 uses a GOP size of 6 for 720p modes to maintain a keyframe rate of at least 8 per second in all video modes. Others may find lower keyframe rates acceptable, but this was an important motion-tracking optimization issue for me. In my testing, I was unable to find GOP-9 settings that produced 720p results verifiably more reliable than FM 2.02's GOP-6 patch.

  • @LPowell about my revisions:

    If boosting the 24H and 24L can compromise the spanning and 30Mbps card performance, just go back to 95000000 bitrate and 32500000. The 128000000 and 64000000 are working ok for me with the Sandisk 32GB SDHC 45Mbps card, but I did not test spanning because I do not need it.

    GOP 9 makes the 720p 60p more stable, GOP 6 stops recording all the time in my tests. The noise, texture and no macroblocking results are ok with GOP 9, it is good quality and stable. I think GOP 9 will be no problem for spanning because in each 3 seconds recording (each 180 frames) the GOP 9 close togheter with GOP 6 in same point of time. Also 2xGOP9 = 3xGOP6 in time.

    The other changes are working for me with the Sandisk 32GB SDHC 45Mbps card. I do not need spanning, so my settings are not optimized for it, my settings are optimized for stable recording and quallity without spanning.

    Maybe you can find a best balance between my settings and your settings to keep it stable and make spanning to work properly, just keep GOP 9 in 720p because it is a must for stability. Quantization 18 helps 720p stability also and no hurt in quality, but maybe 17 also works. The bitrate settings for 720p are also important for stability (72000000 and 56000000), increase or decreasing it hurts stability. For the 1080p settings, if spanning in 1080p 24p is a must, go back to FM202 1080p 24p default settings.

    The important thing is to tweak it to make the 720p to be stable in FM202.

    Thanks.

  • When I test stability and reliability I shoot a green grass under sunlight with high speed shutter and I do movements with the camera, pan, rotate, zoom, to stress the codec. the shutter above 1/1000 is important to avoid motion blur and keep everything sharp when moving the camera, this way the codec will get stressed. The green grass under sunlight is the image which makes the Flow Motion 720p 60p GOP6 to stop recording and sometimes it freezes the camera, needs to remove and insert battery again. 720p with GOP 9 and other tweaks I did in FM202 solves this. The green grass is an image good for test settings in PTools because it strees the codec a lot and keep bitrate very high. If the camera can record the green grass for more than one minute with high shutter and movements, then the settings are ok for other images.

    To test texture, noise and macroblocking I use to shoot a dark low light scene with different colors in image and some black things over light surfaces like inside walls, a room interior shoot. Also increasing the iso to 3200 helps to perceive how the codec handles the noise, texture and macroblocking. FM202 with GOP9 for 720p is working great for this with the tweaks I did. 1080p 24p also working ok.

    It is amazing how FM202 shows the textures and noise, makes GH2 a new camera. Textures, noise, grain, low light, image details and high iso performance improves a lot. No macroblocking and the horizontal lines pattern in high iso is much less disturbing. Also there is no quality changing over time, same performance for I, B and P frames. Spatial and temporal homogeneous image for 720p and 1080p.

    @LPowell did a great job in PTools advanced settings for Testers to improve the encoding performance. I am willing keep Flow Motion tweaked version in GH2 all the time. My tweaks are not optimized for spanning, just for stability, so I hope he can develop a balanced version between the original FM202 and the tweaks I did to make 720p stable and spanning at same time. But maybe spanning in 1080p is enough, because 720p is more usefull for short scenes with slowmotion in post production. So merging the 1080p 24p settings from the original FM202 version with the 720p 60p settings from the tweaked version can be a good mix.

    720p.jpg
    1280 x 720 - 565K
  • I can't believe! The modified Flow Motion makes the GH2 720p 60p usable at iso 12800 and just great at iso 6400. It upscales pretty good to 1080p. I just did a good denoise and add some film grain. There is no reason for me to upgrade for GH3 or GH4 at this moment!

  • @apefos gonna give it a test drive.. How is it in Landscape type shots, or infinity shots? You should post some test videos.

  • Hello @TrackZillas I am doing tests before uploading something. I did some shoots under sunlight with everything in focus in iso 160. I used the 14-42mm kit lens. The image is ok. The GH2 720p is as good as Canon 1080p.

  • @apefos Yeah GH2 is such an amazing camera.. From your Patch which one is better GOP3, or GOP9 ?

  • I found that the shortest the GOP the better the image, but there is a limit before camera stops recording. There is only one patch I did. In the patch GOP 3 is for 1080p 24p and GOP 9 is for 720p 60p. GOP 3 is stable for 1080p 24p and GOP 9 is the shortest GOP stable for 720p. I did not test 60i, 30p or 25p because it is not important for me. All the kudos goes to @LPowell because he did the great job in the matrices and tables, I just tweaked the stability in 720p changing from GOP6 to GOP9 and adjusting the bitrate and quantization.

  • Gotcha will try..

  • @apefos

    I agree Flowmotion is an awesome patch I have my own modified version of that patch on 3=GH2's and I see no reason to use anything else. The bitrates in 24p is moderate and not excessively high LPowell did a remarkable job with this patch.

  • @Azo

    It would be interesting you share your own changes. If you can, please upload the set ini file from your modified Flow Motion.

    Thanks!

    Here is another set ini I did, just changing the quantization back to the original Flow Motion value 17 instead of 18. Not tested yet.

    seth.zip
    9K
  • @apefos

    The modified settings that I worked on is only for HBR30p mode. This was the main concern that I had with all of the patches. I have used Moon T-5/7, Cake V2.3, Sanity, etc etc etc. After extensive testing I found this patch to be the best patch for shooting in 30p mode with a modified Moon T-4 patch as a close second. Attached is my modified setting that will pass the screen of death video in 30p-24p. I have not tested 720p but maybe you could mesh the 2 together then we would have the best of both worlds ;-)

    seta.ini
    9K
  • @Azo

    In my tests I perceived that the SH bitrate for 720p cannot be so much higher than the maximum showed in StreamParser for the green grass shoot. This is to avoid stop recording and camera freeze. Also GOP9 for 720p is the shortest stable gop I found.

    So I just changed 720p from gop6 to gop9 and bitrate SH to 72000000 to improve stability. All other settings are form the original Flow Motion v2.02 I believe this is the first attempt to do the best of both worlds.

    I did not change the 720p top/bottom bitrate limits, their range is different from the SH and H bitrate settings, I left this unchanged to try to keep spanning working. If camera stops recording in 720p you can change the "720p top setting" to 72000 and the "720p bottom setting" to 48000 or 55000. These settings are near the end of the set ini text file.

    setb.zip
    9K
  • this ini file setc is the same of previous setb but it changes the 720p and 1080i top/bottom limits to be in same range of the SH and H bitrate limits. To be honest I do not know if these changes will improve stability or affect spanning comparing to the previous setb file. I will not test it because I am using the seth file which is in a previous post here.

    setc.ini
    9K
  • These are the settings I will keep in my camera, my latest modified Flow Motion. All resolutions and frame rates working ok (ntsc), no stop recording, no camera freeze. Great quality. Very stable, very reliable with the Sandisk 32GB SDHC 45Mbps card. Spanning was not tested. I hope there will be no more firmware changing...

    Thanks.

    setj.ini
    9K
  • If spanning is not important use the setj from previous post. If spanning is important try this seti. In this seti I just changed GOP to 9 for 720p 60p/50p and also for 1080i 60i and changed the SH bitrate to 72000000. All other settings are from original FlowMotion.

    seti.ini
    9K
  • did you test it with panasonic lenses?

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