Need a Tool to read Pixel Aspect ratio of a file

[mlong30]

Hi,

Is there a tool that can determine the pixel aspect ratio in a video file? I have Gspot, but it doesn't tell me pixel aspect ratio.

The reason why I'm asking is because I'm trying to down grade a 1080p video to 480p, and I would like to maintain the correct pixel aspect ratio.


In Sony Vegas I have the following, but know sure when they should be used.


Pixel Aspect Ratio

1.3333 (HDV 1080)
0.9091 (NTSC DV)
1.2121 (NTSC DV Widescreen)
1.0000 (Square)

My source file is from a Canon 5d Mark II, 1080p video, and I want to down grade to 480p for certain customers. I also shot the video with a wide lens.


Thanks.

Matt

[jagabo]

1080p will almost always be square pixel. The main exception is HDV. MediaInfo can probably tell you for sure what your files are. I downloaded a MOV file that claimed to be from a Canon 5D MKII and it was 1920x1080, square pixel.

[PuzZLeR]

Is there a tool that can determine the pixel aspect ratio in a video file? I have Gspot, but it doesn't tell me pixel aspect ratio.

I also agree - get MediaInfo. It's free.

The reason why I'm asking is because I'm trying to down grade a 1080p video to 480p, and I would like to maintain the correct pixel aspect ratio.

When you mean 480p, do you mean 720x480? Or 640x480 (if, for example, you're using an MPEG-4 format)? Both have very different pixel aspect ratios to (mathematically) maintain a 4:3 aspect ratio, the latter using square pixels.

But if your source is wide-screen, and you want to avoid black bands and/or distortion, then 720x480 would need yet another pixel aspect ratio, and a square pixel target would better benefit with 640x360 (or 640x352 if modula(16)=0 is important).

A MediaInfo readout of your Source (rez, aspect ratio which determines pixel aspect ratio) and better description of your Target goals would help. (I do believe Jagabo has a good hunch though.)

[mlong30]

Is there a tool that can determine the pixel aspect ratio in a video file? I have Gspot, but it doesn't tell me pixel aspect ratio.

I also agree - get MediaInfo. It's free.

But if your source is wide-screen, and you want to avoid black bands and/or distortion, then 720x480 would need yet another pixel aspect ratio, and a square pixel target would better benefit with 640x360 (or 640x352 if modula(16)=0 is important).

A MediaInfo readout of your Source (rez, aspect ratio which determines pixel aspect ratio) and better description of your Target goals would help. (I do believe Jagabo has a good hunch though.)

I downloaded MediaInfo, and I resized my 1080p file to 720x480p using virtual dub (lanczos3).

My goal is to downgrade to 720x480p widescreen, but I noticed pixel jerking in certain parts of the video during playback on dvd so I'm guessing my pixel ratio is off.

The following is my source file from the Canon 5D Mark II

General
Complete name : K:\Dvd Projects\Dorothy_Class_Reunion\Friday\MVI_0390.MOV
Format : MPEG-4
File size : 3.36 GiB
Overall bit rate : 47919470

Video
Count : 185
Count of stream of this kind : 1
Kind of stream : Video
Kind of stream : Video
Stream identifier : 0
ID : 1
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format/Url : http://developers.videolan.org/x264.html
InternetMediaType : video/H264
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Codec ID/Url : http://www.apple.com/quicktime/download/standalone.html
Codec : AVC
Codec/Family : AVC
Codec/Info : Advanced Video Codec
Codec/Url : http://developers.videolan.org/x264.html
Codec/CC : avc1
Codec profile : Baseline@L5.0
Codec settings : 1 Ref Frames
Codec settings, CABAC : No
Codec_Settings_RefFrames : 1
Duration : 602602
Duration : 00:10:02.602
Bit rate mode : VBR
Bit rate mode : Variable
Bit rate : 46380433
Bit rate : 46.4 Mbps
Width : 1920
Width : 1 920 pixels
Height : 1080
Height : 1 080 pixels
Original height : 1088
Original height : 1 088 pixels
Pixel aspect ratio : 1.000
Display aspect ratio : 1.778
Display aspect ratio : 16:9
Original display aspect ratio : 1.765
Original display aspect ratio : 16:9
Rotation : 0.000
Frame rate mode : CFR
Frame rate mode : Constant
Frame rate : 29.970
Frame rate : 29.970 fps
Frame count : 18060
Resolution : 8
Resolution : 8 bits
Colorimetry : 4:2:0
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8
Bit depth : 8 bits
Scan type : Progressive
Scan type : Progressive
Interlacement : PPF
Interlacement : Progressive
Bits/(Pixel*Frame) : 0.746
Stream size : 3493621216
Stream size : 3.25 GiB (97%)



The following is my downgraded 720x480p from Virtual Dub (lanczos3).

Count : 267
Video_Format_List : Lagarith
Complete name : K:\Dvd Projects\Dorothy_Class_Reunion\Friday\Video\Source \MVI_0390_720_480.avi
Format : AVI
Codec/Info : Audio Video Interleave
File size : 8.56 GiB
Duration : 10mn 2s
Overall bit rate : 122 Mbps
Stream size : 735481
Stream size : 718 KiB (0%)
Writing library : VirtualDub build 32817/release
Writing library : VirtualDub build 32817/release

Video
Count : 182
Kind of stream : Video
Format : Lagarith
Codec/Info : Lagarith LossLess
Codec/CC : LAGS
Duration : 10mn 2s
Duration : 00:10:02.603
Bit rate : 120 Mbps
Width : 720
Width : 720 pixels
Height : 480
Height : 480 pixels
Pixel aspect ratio : 1.000
Display aspect ratio : 1.500
Display aspect ratio : 3:2
Frame rate : 29.970
Frame rate : 29.970 fps
Frame count : 18060
Standard : NTSC
Color space : RGB
Bit depth : 8
Bit depth : 8 bits
Bits/(Pixel*Frame) : 11.628
Stream size : 8.45 GiB (99%)


1. What should the correct Pixel aspect ratio be for 720x480p widescreen NTSC?

2. Should I also maintain the same colorspace for playback on NTSC? I'm wondering if this is why the color white in the video is over exposed during playback on TV, but fine during playback on computer.

3. I also selected 16:9 within my encoder, and I see 3:2 instead of 16:9 according to mediainfo, any ideas why?


The following is the VOB file according to MediaInfo

General
Count : 267
Count of stream of this kind : 1
Codecs Video : MPEG-2 Video
Audio_Format_List : AC-3
Menu_Format_List : DVD-Video
Complete name : C:\DVDVolume\VIDEO_TS\VTS_01_1.VOB
File extension : vob
Format : MPEG-PS
Codec : MPEG-PS
File size : 1 000.0 MiB
Duration : 21mn 54s
Overall bit rate : 6382628
Stream size : 19.9 MiB (2%)

Video
Count : 182
Count of stream of this kind : 1
Kind of stream : Video
Stream identifier : 0
Format_Commercial : MPEG-2 Video
Format version : Version 2
Format profile : Main@Main
Format settings : BVOP
Format settings, BVOP : Yes
Format settings, BVOP : Yes
Format settings, Matrix : Default
Format settings, Matrix : Default
Format settings, GOP : M=2, N=15
InternetMediaType : video/MPV
Codec : MPEG-2V
Duration : 21mn 54s
Bit rate mode : VBR
Bit rate mode : Variable
Bit rate : 6063614
Bit rate : 6 064 Kbps
Nominal bit rate : 9800000
Nominal bit rate : 9 800 Kbps
Width : 720
Width : 720 pixels
Height : 480
Height : 480 pixels
Pixel aspect ratio : 1.185
Display aspect ratio : 1.778
Display aspect ratio : 16:9
Frame rate : 29.970
Frame rate : 29.970 fps
Frame count : 39390
Standard : NTSC
Resolution : 8
Resolution : 8 bits
Colorimetry : 4:2:0
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8
Bit depth : 8 bits
Scan type : Progressive
Scan type : Progressive
Scan order : BFF
Scan order : Bottom Field First
Interlacement : PPF
Interlacement : Progressive
Bits/(Pixel*Frame) : 0.585
Delay_Original_Settings : drop_frame_flag=0 / closed_gop=1 / broken_link=0
Stream size : 950 MiB (95%)
BufferSize : 229376


Thanks.
Matt

[manono]

1. I have no idea what you mean by 'pixel jerking' but your 1920x1080 source should probably be resized to 704x480, with 8 columns of pixels added to both sides if you want to make it 720x480.
2. When going from Hi-Def to Std-Def you have to change from Rec. 709 to Rec. 601. I have no idea whether or not VDub can do that. Me, I'd use an AviSynth script for frameserving into VDub to create the Lagarith AVI (at the same time changing the color matrix) and then again to frameserve the Lagarith AVI into my MPEG-2 encoder.
3. It is 16:9 after coming out of the MPEG-2 encoder, according to MediaInfo. Of course the Lagarith.avi is only 3:2. It doesn't really carry DAR information.

Also, I think you screwed up allowing the Lagarith AVI to convert to RGB when both the source and the MPEG-2 final output are YUV. That's probably where your whites (and blacks) got messed up.