Bitrate of each frame in a H.264 file?

ssuave · 28th June 2012, 19:02

Hi,

I wonder how can we compute/extract bit-rate for each frame of an H.264 encoded video file?
Parse the bit-stream somehow and then collect this info but how?

Any ideas/hints on it?

Thanks!

Ma-Xell · 30th June 2012, 13:29

Hi,

Bitrate is usually specified in kbit or mbit per second and if your video is for example 25 frames in a second, then its very simple.
This of course would give the average for one frame across the whole video.
But why would you need this info?

ssuave · 30th June 2012, 13:36

Quote:

Originally Posted by Ma-Xell

Hi,

Bitrate is usually specified in kbit or mbit per second and if your video is for example 25 frames in a second, then its very simple.
This of course would give the average for one frame across the whole video.
But why would you need this info?

Hi,

Thanks but averaging doesn't seem to be good solution for me. I need the exact bit-rate for each encoded frame, otherwise known as 'residual frame' obtained after motion compensation.

Andouille · 30th June 2012, 13:50

ffdshow has an option for displaying the size of each frame.
If it is not enough for ya, since ffdshow is based on ffmpeg, you should have some command in ffmpeg to output a log with the frame number/type/size (I guess)

Guest · 30th June 2012, 13:53

Quote:

Originally Posted by ssuave

I wonder how can we compute/extract bit-rate for each frame of an H.264 encoded video file?
Parse the bit-stream somehow and then collect this info but how?

If you want to create your own code for this, rather than using an existing utility to dump the frame sizes, you get the H.264 spec and read the part where it tells how to recognize the start of a new frame in the bitstream. Then you parse the bitstream to find these boundaries. The boundaries let you determine the frame sizes. You have the frame rate and so you have the time per frame. Now you have everything you need to calculate the bitrate for any frame.

If you are asking how to parse H.264, then that is also described in the spec.

There is sample code in the JM reference decoder that I used as the basis for the H.264 parsing in my tools.

upyzl · 1st July 2012, 03:11

obieobieobie · 3rd July 2012, 18:33

It's actually impossible to have a bit rate for a still image.

Guest · 3rd July 2012, 18:42

Quote:

Originally Posted by obieobieobie

It's actually impossible to have a bit rate for a still image.

If you have a defined display time for the image then the concept of bitrate for the image has a meaning.

poisondeathray · 3rd July 2012, 18:57

A free way is ffdshow's osd (checkmark "coded frame size"), it has option to print out csv file

A non free way is to use a stream parser like elecard streameye

obieobieobie · 4th July 2012, 16:26

Quote:

Originally Posted by neuron2

If you have a defined display time for the image then the concept of bitrate for the image has a meaning.

Yes, you are of course correct.

ssuave · 25th July 2012, 14:07

Hi,
Thanks all. I appreciate it!

28th June 2012, 19:02	#1 \| Link
ssuave Registered User Join Date: Jan 2012 Location: Sweden Posts: 18	Bitrate of each frame in a H.264 file? Hi, I wonder how can we compute/extract bit-rate for each frame of an H.264 encoded video file? Parse the bit-stream somehow and then collect this info but how? Any ideas/hints on it? Thanks!

1st July 2012, 03:11	#6 \| Link
upyzl zj262144 Join Date: Sep 2010 Posts: 105	Attached Images __________________ MPC-HC 1.7.8 / LAV Filters 0.64+ (tMod) / XySubFilter 3.1.0.705 / madVR 0.87.14 Direct264 Mod (src & win32 builds): code.google.com/p/direct264umod (maybe outdated)

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30th June 2012, 13:29	#2 \| Link
Ma-Xell Somewhere Back in Time Join Date: Jul 2008 Location: Hungary Posts: 61	Hi, Bitrate is usually specified in kbit or mbit per second and if your video is for example 25 frames in a second, then its very simple. This of course would give the average for one frame across the whole video. But why would you need this info?

30th June 2012, 13:50	#4 \| Link
Andouille Registered sausage Join Date: May 2012 Posts: 78	ffdshow has an option for displaying the size of each frame. If it is not enough for ya, since ffdshow is based on ffmpeg, you should have some command in ffmpeg to output a log with the frame number/type/size (I guess)

3rd July 2012, 18:33	#7 \| Link
obieobieobie Registered User Join Date: Mar 2004 Posts: 182	It's actually impossible to have a bit rate for a still image.

3rd July 2012, 18:57	#9 \| Link
poisondeathray Registered User Join Date: Sep 2007 Posts: 5,285	A free way is ffdshow's osd (checkmark "coded frame size"), it has option to print out csv file A non free way is to use a stream parser like elecard streameye

25th July 2012, 14:07	#11 \| Link
ssuave Registered User Join Date: Jan 2012 Location: Sweden Posts: 18	Hi, Thanks all. I appreciate it!