Change display aspect ratio without changing width and height

Wowza Streaming Engine
1

Hello,

We are streaming with Adobe Flash Media Live Encoder into our wowza server a PAL video with 720x756 pixels anamorphic (16:9).

We configured the transrate.xml file like this:

true

test

mp4:${SourceStreamName}_test

We get an output stream from wowza media server like this:

General

ID : 1 (0x1)

Complete name : media.ts

Format : MPEG-TS

File size : 2.67 MiB

Duration : 9s 960ms

Overall bit rate mode : Variable

Overall bit rate : 2 239 Kbps

Video

ID : 256 (0x100)

Menu ID : 1 (0x1)

Format : AVC

Format/Info : Advanced Video Codec

Format profile : Main@L3.1

Format settings, CABAC : Yes

Format settings, ReFrames : 3 frames

Codec ID : 27

Duration : 10s 0ms

Bit rate mode : Variable

Maximum bit rate : 1 980 Kbps

Width : 720 pixels

Height : 576 pixels

Display aspect ratio : 5:4

Frame rate : 25.000 fps

Standard : NTSC

Color space : YUV

Chroma subsampling : 4:2:0

Bit depth : 8 bits

Scan type : Progressive

Audio

ID : 257 (0x101)

Menu ID : 1 (0x1)

Format : AAC

Format/Info : Advanced Audio Codec

Format version : Version 4

Format profile : LC

Muxing mode : ADTS

Codec ID : 15

Duration : 9s 891ms

Bit rate mode : Variable

Minimum bit rate : 85.1 Kbps

Maximum bit rate : 139 Kbps

Channel(s) : 2 channels

Channel positions : Front: L R

Sampling rate : 44.1 KHz

Compression mode : Lossy

Delay relative to video : 19ms

We would like to get this parameters:

Width : 720 pixels

Height : 576 pixels

Display aspect ratio : 16:9 (instead of 5:4)

Frame rate : 25.000 fps

Standard : PAL (instead of NTSC)

Is there a way to obtain these results changing some parameters of the transrate.xml file?

Thanks for advance,

Moisès

2

Moisès,

The Wowza Transcoder does not support anamorphic squeeze encoding. It does support decode of video with anamorphic squeeze, but not encode. So the Display aspect ratio is only a function of Width and Height

You will have to verify following this guide but you can probably set the encode to PAL by adding this Parameter to each Transcoder template /Encode /Video Parameters container:

<Parameter>
    <Name>mainconcept.video_format</Name>
    <Value>1</Value>
    <Type>Long</Type>
</Parameter>

Look for this output in the access log with the logVideoEncodingParameters Property enabled to verify your system has this feature.

INFO server comment - # long: vui parameters: 1: PAL, 2: NTSC
INFO server comment - mainconcept.video_format: 2

Richard

3

Thanks for the update, Moisès. Glad it’s working

Richard

4

Richard,

Many thanks for your help.

Regards,

Moisès

5

Hi again,

Finally, we achieved everything we needed.

The output of the access log was very helpfull:

INFO 200 - # long: vui parameters: sample aspect ratio: horizontal size in arbitrary units

INFO 200 - mainconcept.sar_width: 1

INFO 200 - # long: vui parameters: sample aspect ratio: vertical size in arbitrary units

INFO 200 - mainconcept.sar_height: 1

So we modified the transrate template to also obtain 16:9 aspect ratio with a 720x576 video resolution. We configured the pixel ratio as 16:11 (for an anamorphic wide screen; 16:9 => http://en.wikipedia.org/wiki/Pixel_aspect_ratio):

mainconcept.video_format

1

Long

mainconcept.sar_width

16

Long

mainconcept.sar_height

11

Long

So we got this:

Width : 720 pixels

Height : 576 pixels

Display aspect ratio : 16:9

Frame rate : 25.000 fps

Standard : PAL

Regards,

Moisès

6

You may also refer to this step by step guide on how to change video aspect ratio among 4:3, 16:9, 2.35:1, 1.85:1, 1:1, 21:9 etc

7

Just google search Step by Step Guide on How to Change Video Aspect Ratio with iDealshare VideoGo, you will find a detailed guide.

8

HI, I think the best and simple way is use some kind of software, don’t need the coding staffs. I usually use the HD Video Converter Factory Pro to change aspect ratio of video to solve this kind of things. Hope it will help you.

Best