Aspect ratio for extracted frame

[sapzxc]

Help me guys with this: I test video 640x480.

Its normal video, without rotation. Extracted frame looks like:

Then I rotate video and then extract same frame:

There aspect ratio trouble. When I manually set aspect ratio - it looks good. First minds is extracting video dimensions and put aspect ration to "extract frame" code. Is it good idea or exists another workaround?

[buggedcom]

Hi there. Can you attach the code you are using please?

[buggedcom]

or at least capture and output the commands being sent to ffmpeg

[sapzxc]

See my gist https://gist.github.com/sapzxc/10171091

download it, then run test.sh It creates 1.mp4 1.jpg - normal, 2.mp4 2.jpg - rotated video and frame.

[buggedcom]

Thanks. I'm looking into it now. As i see it the problem can be described as:

1.mp4 - ok 1.jpg - ok 2.mp4 - ok 2.jpg - error

I'm just adding the raw commands below for future reference:

/opt/local/bin/ffmpeg '-i' '/Users/ollie/Downloads/gist10171091-ac8a4c4061036610fea01e0aed53fea39d8b9835/1.mov' '-y' '-qscale' '4' '-f' 'mp4' '-strict' 'experimental' '-threads' '1' '-acodec' 'aac' '-ab' '96k' '-ar' '48000' '-ac' '2' '-vcodec' 'h264' '-s' '640x480' '-b:v' '2500k' '-profile:v' 'main' '/Users/ollie/Downloads/gist10171091-ac8a4c4061036610fea01e0aed53fea39d8b9835/1.mp4'
/opt/local/bin/ffmpeg '-i' '/Users/ollie/Downloads/gist10171091-ac8a4c4061036610fea01e0aed53fea39d8b9835/1.mp4' '-y' '-ss' '00:00:12.00' '-qscale' '4' '-f' 'image2' '-strict' 'experimental' '-threads' '1' '-an' '-vcodec' 'mjpeg' '-r' '1' '-vframes' '1' '/Users/ollie/Downloads/gist10171091-ac8a4c4061036610fea01e0aed53fea39d8b9835/1.jpg'
/opt/local/bin/ffmpeg '-i' '/Users/ollie/Downloads/gist10171091-ac8a4c4061036610fea01e0aed53fea39d8b9835/1.mov' '-y' '-qscale' '4' '-f' 'mp4' '-strict' 'experimental' '-threads' '1' '-acodec' 'aac' '-ab' '96k' '-ar' '48000' '-ac' '2' '-vcodec' 'h264' '-s' '640x480' '-b:v' '2500k' '-vf' 'transpose=1' '-profile:v' 'main' '/Users/ollie/Downloads/gist10171091-ac8a4c4061036610fea01e0aed53fea39d8b9835/2.mp4'
/opt/local/bin/ffmpeg '-i' '/Users/ollie/Downloads/gist10171091-ac8a4c4061036610fea01e0aed53fea39d8b9835/2.mp4' '-y' '-ss' '00:00:12.00' '-qscale' '4' '-f' 'image2' '-strict' 'experimental' '-threads' '1' '-an' '-vcodec' 'mjpeg' '-r' '1' '-vframes' '1' '/Users/ollie/Downloads/gist10171091-ac8a4c4061036610fea01e0aed53fea39d8b9835/2.jpg'

[buggedcom]

Looking at the command strings, it would appear as if you have possibly found an issue with ffmpeg. Although I'm not 100% sure. The command strings look as if they should generate the correct thumbnails.

[buggedcom]

Hmmm. It seems that ffmpeg doesn't re-encode the correct video dimensions once rotated, although it does store the aspect ratio correctly.

This is the output from $video->read() when inspecting 2.mp4

    [video] => Array
        (
            [stream] => 0:0
            [dimensions] => Array
                (
                    [width] => 640
                    [height] => 480
                )

            [bitrate] => 664000
            [time_bases] => Array
                (
                    [fps] => 10
                    [tbr] => 10
                    [tbn] => 10240
                    [tbc] => 20
                )

            [frames] => Array
                (
                    [total] => 250
                    [rate] => 10
                    [avg_rate] => 
                )

            [pixel_aspect_ratio] => 9:16
            [display_aspect_ratio] => 3:4
            [rotation] => 
            [pixel_format] => yuv420p
            [language] => eng
            [codec] => Array
                (
                    [name] => h264
                    [profile] => Main
                    [tag_string] => 0x31637661
                    [tag] => avc1
                    [raw] => h264 (Main) (avc1 / 0x31637661)
                )

            [metadata] => Array
                (
                    [handler_name] => VideoHandler
                )

        )

You can see that the width and height are not correct, however the aspect ratio is. A bit annoying, but I'm sure I can add some additional checks to make sure the width and height obey aspect ratio.

[buggedcom]

Interestingly if you re-encode 2.mp4 using fetch.php to just be 2a.mp4 the aspect ratio is also borked.

[sapzxc]

As I understand we must setup aspect ratio with transcode operation.

Similar issues (search on page by "aspect" keyword): https://github.com/rheaton/carrierwave-video/issues/21 http://superuser.com/questions/630433/rotate-a-video-90-degrees http://stackoverflow.com/questions/21709900/ffmpeg-conditional-rotation-of-video

[buggedcom]

created an automatic patch so that PHPVideoToolkit detects this silliness and automatically applies dimension commands when needed. It is in the head of master. I will create a tag shortly. Thanks for finding the bug.

[buggedcom]

fixed in fb302e32d4eae6c654524d8c39779e123fe1c3a6

[buggedcom]

Related tag: https://github.com/buggedcom/phpvideotoolkit-v2/releases/tag/2.1.6-beta

[buggedcom]

argh. Just read your links. Seems whilst this fix does actually work, the links suggest a better alternative.

[buggedcom]

Whilst this patch will do what you want, and I will create a further patch, you xould in the mean time just call $video->setVideoAspectRatio() yourself?

[sapzxc]

Something wrong: I added $outputFormat->setVideoAspectRatio('3:4');

Got:

CommandString: /usr/bin//ffmpeg '-i' '/usr/www/fmqa/public/test/1.mov' '-y' '-qscale' '4' '-f' 'mp4' '-strict' 'experimental' '-threads' '1' '-acodec' 'aac' '-ab' '96k' '-ar' '48000' '-ac' '2' '-vcodec' 'h264' '-s' '540x405' '-aspect' '3:4' '-b:v' '2500k' '-vf' 'transpose=1' '-profile:v' 'main' '/usr/www/fmqa/public/test/2.mp4'

Actual error: height not divisible by 2 (540x405) Its because: yuv420p

But why it made dimensions 540x405 from 640x480?

[buggedcom]

It could be there is a bug in the aspect ratio setting. By default it should not automatically adjust the width and height to fit the new ratio, however I guess there might be a bug somewhere if it is resizing it unexpectedly. will look into that too.

[buggedcom]

bugs fixed and methods updated in master. Please let me know if it works for you now.

[sapzxc]

Now my test works and image has proper aspect. But strange dimensions still there. 1.mp4: '-s' '640x480' - good 2.mp4: '-s' '360x270' '-aspect' '3:4' - wrong? It should be 640x480 or 480x640, but why 360x270?

ffprobe of 1.mp4 and 2.mp4: Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 640x480 [SAR 1:1 DAR 4:3], Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 360x270 [SAR 9:16 DAR 3:4]

Now investigating...

[buggedcom]

It's todo with Video::setVideoDimensions

setVideoDimensions($width, $height=null, $auto_adjust_dimensions_to_optimal=false, $force_aspect_ratio=false)

In the previous version the $auto_adjust_dimensions_to_optimal placeholder was defaulting to true. Can you check that file to see if it's updated for you?

[sapzxc]

Updated scripts and it works! But have another issue with size, You hate me I know =)

Source file is 640x480. First not rotated file has size 1280x720 Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 1280x720 [SAR 3:4 DAR 4:3]

And rotated 360x480 Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 360x480 [SAR 1:1 DAR 3:4]

Looks like need setup source size everywhere or destination size everywhere. I think it should be source size if it smaller than destination. It should not scale video in to bigger size.

[buggedcom]

No worries, glad to help, but I'm not entirely sure of what you mean?

[sapzxc]

Oh, I understand, my last comment is wrong. I was playing with code and there was error. Now works, I got one file 1024x768 and second 540x720. Good.

But if I want preserve source dimensions I write: ->setVideoDimensions(\PHPVideoToolkit\VideoFormat::DIMENSION_HD720,null,true) Then I got normal first file without rotation. ok. But when I try rotate I got error related to pixel aspect ratio, because size now 540x405.

I investigated, its because getOptimalDimensions called with 540, 720 params as target size and then function trimmed height to 405. But why it calculate in this way? If I have 640x480 - I must get optimal size 360x480 - it is actual optimal size. Why used that algorithm?

[buggedcom]

Did you manage to sort this out? Was there an error in the algorithm? It looks as if the wrong dimension is being used to calculate the optimum size.

[sapzxc]

Sorry for the delay of my response. I have created fork for last version on 2014-06-18 and added here tests based on phpunit. Using tests we can define default behavior of the framework. You also consider?

Now I bumped of this issue: When I convert smaller video to HD - I got bigger video. So I use param $auto_adjust_dimensions_to_optimal , but when I set it to true - I got error "Error while opening encoder for output stream #0:0 - maybe incorrect parameters such as bit_rate, rate, width or height".

Also I writed test for function getOptimalDimensions and it also working not as I expected.

I can manage with this after month (as I expecting). My project will be in tests and bugfixes stage, so I will check and fix all.