1 VAS Intro

1.1 Brief Introduction

Most short video users provide video uploading functions and support video sharing. However, many UGC users upload videos with different resolutions. Even through resolution conversion, the video may have black bars around it after scaling. For this kind of abnormal video, you can use Video Cropping to cut out the black bars and improve the viewing experience.

For example, if the resolution of the uploaded video is 1920 * 1920, and the resolution of the target video is 1920 * 1080, system will scale it to 1080 * 1080 first, and then fill the black bars on the video left and right sides to match 1920 * 1080, that is to say, there are black bars existed on the left and right sides of the watched video. In this case, Video Cropping can be used to cut out the black bars to make it more beautiful.

1.2 Applicable Product Line

Media Acceleration

1.3 Application Scenario

This feature is applicable for scenarios such as live video recording and PGC/UGC which requires video/audio content processing. For example, When a customer needs to crop black bars of the video, to improve viewing experience.

2 VAS Detail

2.1 VAS Description

Supports common video/audio encapsulation formats and encoding formats, such as:
(1) Video formats: MP4, fMP4, FLV, M3U8, TS, MKV, MOV, WMV, AVI, VP8, VP9, RealVideo, Windows Media Video, etc.;
(2) Audio formats: AAC, AC-3, MP1, MP2, MP3, PCM, RealAudio, Windows Media Audio (WMA), OGG, etc.;
(3) Encoding Formats: H.265, H.264, H.263, MPEG, etc.

2.2 Instructions

When uploading video/audio files, customers can configure the VoD file processing parameters at the same time without calling the API separately. If the customer has not enabled the VoD file processing feature, the file processing parameters will be invalid even though they have been uploaded by the API.
The VoD file processing feature can be used together with the VoD Video/Audio Transcoding and VoD Transmuxing, that is, these features can be realized through a single API command concatenation.

2.3 Interface Description

2.3.1 Request Description

Request parameters are organized in the following format and submitted as request content:

bucket=<Urlsafe_Base64_Encoded_Bucket>&key=<Urlsafe_Base64_Encoded_Key>&fops=<Urlsafe_Base64_Encoded_Fops>&notifyURL=<Urlsafe_Base64_Encoded_PersistentNotifyUrl>&force=&separate=

Table 1 Request Parameter Description

Apart from filling in the parameters in the following format, fill the URL-Safe Base64 Encoding values in the fops parameter:

<op>/<Format>
    /gravity/<gravity>
    /vcrop/<vcrop>
    |saveas/<Urlsafe_Base64_Encode(bucket:filekey)>

Table 2 Video Cropping Parameters

Table 3 Video Offset Parameters

Table 4 Video Cropping Operation Parameters

2.3.2 Response Description

If the request succeeds, return the following Json character string:

{ "persistentId": <persistentId> } 

If the request fails, return the following Json character string:

{
  "code": "<code string>",
  "message":  "<ErrMsg string>"
} 

Table 5 Response Parameter Description

2.4 Usage Example

Crop the test.mp4 video under the vod-wcs-test001 bucket, and output two videos:

• Crop 400*352 out of the top left corner of the test.mp4 video, save it as m4a format, and name it as test_file.m4a;
• Crop 200*352 out of the center of the test.mp4 video, save it as flv format, and name it as test_file.flv.

curl -v -X POST –d "bucket=Urlsafe_Base64_Encode(vod-wcs-test001)&key=Urlsafe_Base64_Encode(test.mp4)&fops=Urlsafe_Base64_Encode(avthumb/m4a/gravity/TOP_LEFT/vcrop/400x352|saveas/Urlsafe_Base64_Encode(vod-wcs-test001:test_file.m4a);avthumb/flv/gravity/CENTER/vcrop/200x352|saveas/Urlsafe_Base64_Encode(vod-wcs-test001:test_file.flv))&force=1&separate=1" –H "Authorization:mgrAuthorization_A:mgrAuthorization_B" --url "http://mgrDomain/fops"

After encryption:

curl -v -X POST -d"bucket=dm9kLXdjcy10ZXN0MDAx&key=dGVzdC5tcDQ=&fops=YXZ0aHVtYi9tNGEvZ3Jhdml0eS9UT1BfTEVGVC92Y3JvcC80MDB4MzUyfHNhdmVhcy9kbTlrTFhkamN5MTBaWE4wTURBeE9uUmxjM1JmWm1sc1pTNXROR0VLQ2c9PTthdnRodW1iL2Zsdi9ncmF2aXR5L0NFTlRFUi92Y3JvcC8yMDB4MzUyfHNhdmVhcy9kbTlrTFhkamN5MTBaWE4wTURBeE9uUmxjM1JmWm1sc1pTNW1iSFlLQ2c9PQoK&force=1&separate=1" -H "Authorization:mgrAuthorization_A:mgrAuthorization_B" --url "http://mgrDomain/fops"

Tips:

1. mgrAuthorization_A:mgrAuthorization_B: Utilize AK, SK, path and Body to generate the access token Authorization through tools. AK, SK: find it from “Console-Account Management-API information Management-AccessKey Management”, Path: it’s /fops，Body: it’s the request content Body.
2. mgrDomain: Management Domain, find it from “Console-Object Storage-The related Bucket-Overview”.

3 Notice

1. Video Cropping is a VAS which means you need to pay for it, please enable the VAS of VoD File Processing.
2. Video Cropping only manipulate video files stored on CDNetworks Object storage, so Media Acceleration-VOD and Object storage products should be enabled at the same time.