How to change bit rate?

Started by keisersozze, September 24, 2012, 05:00:46 AM

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keisersozze

Will I be able to change the bit rate to 66 if I install v2.3 release? If so, how? Maybe someone can point me in the right direction. I just got a Canon and I'm unable to find any info regarding how to do this. I'm new to hacking also so don't assume I know anything.
Thanks

Francis

66 whats? If you just got a Canon camera, spend a couple months figuring out how to use it. Then come back and see us.

nanomad

The only 66 that makes sense is the FPS and the answer is no
EOS 1100D | EOS 650 (No, I didn't forget the D) | Ye Olde Canon EF Lenses ('87): 50 f/1.8 - 28 f/2.8 - 70-210 f/4 | EF-S 18-55 f/3.5-5.6 | Metz 36 AF-5

keisersozze

I mean how do I get 66Mbit?

I'm going on a long vacation soon and would like to maximize my video recording. According to several articles bit rate can be increased from 42Mbit to 66Mbit or 76Mbit, 76 not being as reliable.
Below is one such article if anyone is still confused.

eoshd.com/content/466/canon-5d-mark-ii-hack-brings-66mbit-1080p

Thanks.

nanomad

Just go to the bitrate sub-menu and increase it from there. There's no "XX Mbit" value because the canon firmware doesn't work that way
EOS 1100D | EOS 650 (No, I didn't forget the D) | Ye Olde Canon EF Lenses ('87): 50 f/1.8 - 28 f/2.8 - 70-210 f/4 | EF-S 18-55 f/3.5-5.6 | Metz 36 AF-5

keisersozze

Quote from: nanomad on September 24, 2012, 06:02:10 PM
Just go to the bitrate sub-menu and increase it from there. There's no "XX Mbit" value because the canon firmware doesn't work that way

Thank you. That's pretty much all I needed to know. I did not know there was a bitrate menu. Do you know what increase options are available and which one would match what I'm looking for? Again I can't seem to find any info on this.

skydragon

If you go into ML's 'Movie' menu and select the first item 'Bit rate CBR' this menu item then effectively changes the video bitrate.

The standard video bitrate (CBR x 1.0) on my Canon 600D (t3i) is approx 42 Mbps.

If I select ML to a CBR x 1.4 this then results in a bitrate of around 61Mbps

However....Be aware that increasing the bitrate can have some unwanted side effects

1. You will need a very fast memory card if you want to record video at increased bitrates. I tried a Sandisk 45 MBps card in my 600D and although it did seem to record at CBR x 1.4 (approx 61Mbps), it had an annoying glitch after approx 1 second of video, which looked like some frames had dropped. I then upgraded my memory card to a Sandisk 95MBps card and it now works fine at CBR x1.4 on my 600D.

2. Turning audio 'off' in your cameras main menu will make video recording at higher bitrates easier.

3. If I play back a CBR x1.4 video on my Canon 600D, it will only play back approx 6 seconds of video before it then stops. it seems that the 600D camera cannot sustain playback of such a high bitrate video file. If I play the video file back on a PC then everything is ok and the video looks great. This is not a major problem for me. But it is annoying and means I cannot audition whole video files on the camera after shooting, without a PC on hand.

BTW I'm a noob to ML, so still learning (BTW - Many thanks to the ML guys, you rock!) but hopefully the above info helps you a bit
Canon 600D with Battery Grip, ML 2.3, Sigma 17-50mm 2.8, Swivi viewfinder loupe, RJ Follow focus. Loupe, FF and Camera/Battery Grip mounted on a 4mm thick alloy plate.

1%

Will never get a steady 1 number bit rate. Camera is VBR 100% of the time. CBR just does prediction on the next frame and lowers/raises quality. Just set CBR to some number or qscale if you know scene won't change too much.

T3i goes waaaay higher than that :)

skydragon

Thanks for background 1%

Ref reliable playback of CBR x1.4 video files on t3i, is there any way to get the camera to playback video files circa 60-70Mbps for more than 5 - 7 secs?

ie. Is this a limitation of the t3i processing/design, a ML bug, or finger trouble on my part?
Canon 600D with Battery Grip, ML 2.3, Sigma 17-50mm 2.8, Swivi viewfinder loupe, RJ Follow focus. Loupe, FF and Camera/Battery Grip mounted on a 4mm thick alloy plate.

1%

Not really. I'm assuming even CBR 1.4/2.0 violates the hardware player spec. Avinaptic throws a violation on every frame I make and I'm glad. I set picqpy and the HW player makes the luma blink because its too stupid to play it back. I've kinda given up on the player.

skydragon

Thanks for the confirmation. I can live with this limitation in the camera for the $ versus performance ratio it gives  :)
Canon 600D with Battery Grip, ML 2.3, Sigma 17-50mm 2.8, Swivi viewfinder loupe, RJ Follow focus. Loupe, FF and Camera/Battery Grip mounted on a 4mm thick alloy plate.

keisersozze

I've heard about these issues but as I understand this is only 'in-camera viewing' and there are 0 issues when its transfered to the computer no matter what bitrate is set?

1%

No worries, plays back fine and edits great.

keisersozze

Great. Thanks for all the help.