ThetaDev
c8e2d342c6
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378 lines
9.8 KiB
Markdown
378 lines
9.8 KiB
Markdown
# A/B-Tests
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When YouTube introduces a new feature, it does so gradually. When a user creates a new
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session, YouTube decided randomly which new features should be enabled.
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YouTube sessions are identified by the visitor data cookie. This cookie is sent with
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every API request using the `context.client.visitor_data` JSON parameter. It is also
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returned in the `responseContext.visitorData` response parameter and stored as the
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`__SECURE-YEC` cookie.
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By sending the same visitor data cookie, A/B tests can be reproduced, which is important
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for testing alternative YouTube clients.
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This page lists all A/B tests that were encountered while maintaining the RustyPipe
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client.
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**Impact rating:**
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The impact ratings shows how much effort it takes to adapt alternative YouTube clients
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to the new feature.
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- 🟢 **Low** Minor incompatibility (e.g. parameter name change)
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- 🟡 **Medium** Extensive changes to the response data model OR removal of parameters
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- 🔴 **High** Changes to the functionality of YouTube that will require API changes for
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alternative clients
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If you want to check how often these A/B tests occur, you can use the `codegen` tool
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with the following command: `rustypipe-codegen ab-test <id>`.
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## [1] Attributed text description
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- **Encountered on:** 24.09.2022
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- **Impact:** 🟡 Medium
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- **Endpoint:** next (video details)
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![A/B test 1 screenshot](./_img/ab_1.png)
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YouTube shows internal links (channels, videos, playlists) in the video description as
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buttons with the YouTube icon. To accomplish this, they completely changed the
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underlying data model.
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The new format uses a string with the entire plaintext content along with a list of
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`"commandRuns"` which include the link data and the position of the links within the
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text.
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Note that the position and length parameter refer to the number of UTF-16 characters. If
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you are implementing this in a language which does not use UTF-16 as its internal string
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representation, you have to iterate over the unicode codepoints and keep track of the
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UTF-16 index seperately.
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**OLD**
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```json
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{
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"videoSecondaryInfoRenderer": {
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"description": {
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"runs": [
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{
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"text": "🎧Listen and download aespa's debut single \"Black Mamba\": "
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},
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{
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"navigationEndpoint": {
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"commandMetadata": {
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"webCommandMetadata": {
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"rootVe": 83769,
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"url": "https://www.youtube.com/redirect?...",
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"webPageType": "WEB_PAGE_TYPE_UNKNOWN"
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}
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},
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"urlEndpoint": {
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"nofollow": true,
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"target": "TARGET_NEW_WINDOW",
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"url": "https://www.youtube.com/redirect?..."
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}
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},
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"text": "https://smarturl.it/aespa_BlackMamba"
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}
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]
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}
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}
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}
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```
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**NEW**
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```json
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{
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"videoSecondaryInfoRenderer": {
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"attributedDescription": {
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"content": "🎧Listen and download aespa's debut single \"Black Mamba\": https://smarturl.it/aespa_BlackMamba\n🐍The Debut Stage...",
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"commandRuns": [
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{
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"startIndex": 58,
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"length": 36,
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"onTap": {
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"innertubeCommand": {
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"commandMetadata": {
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"webCommandMetadata": {
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"url": "https://www.youtube.com/redirect?...",
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"webPageType": "WEB_PAGE_TYPE_UNKNOWN",
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"rootVe": 83769
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}
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},
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"urlEndpoint": {
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"url": "https://www.youtube.com/redirect?...",
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"target": "TARGET_NEW_WINDOW",
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"nofollow": true
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}
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}
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}
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}
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]
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}
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}
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}
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```
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## [2] 3-tab channel layout
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- **Announced:** 15.09.2022, https://www.youtube.com/watch?v=czIyqEC4V-s
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- **Encountered on:** 11.10.2022
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- **Impact:** 🔴 High
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- **Endpoint:** browse (channel videos)
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![A/B test 2 screenshot](./_img/ab_2.webp)
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YouTube changed their channel page layout, putting livestreams and short videos into
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separate tabs.
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Fetching the videos page now only returns a subset of a channel's videos. To get all
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videos from a channel, you would have to run up to 3 queries.
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Even though it has its disadvantages, the RSS feed is now probably the best way for
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keeping track of a channel's new uploads.
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Additionally the channel tab response model was slightly changed, now using a
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`"RichGridRenderer"`. Short videos also have their own data models
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(`"reelItemRenderer"`).
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**RichGrid**
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```json
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{
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"tabRenderer": {
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"content": {
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"richGridRenderer": {
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"contents": [
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{
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"richItemRenderer": {
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"content": {
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"videoRenderer": {}
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}
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}
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}
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]
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}
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}
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}
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}
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```
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**Short video**
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```json
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{
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"reelItemRenderer": {
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"accessibility": {
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"accessibilityData": {
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"label": "being smart was my personality trait - 56 seconds - play video"
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}
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},
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"headline": {
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"simpleText": "being smart was my personality trait"
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},
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"navigationEndpoint": {
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"clickTrackingParams": "CLcCEIf2BBgAIhMImuP85t-D-wIVd-sRCB2r6gl7",
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"commandMetadata": {
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"webCommandMetadata": {
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"rootVe": 37414,
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"url": "/shorts/glyJWxp7a5g",
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"webPageType": "WEB_PAGE_TYPE_SHORTS"
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}
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},
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"reelWatchEndpoint": {
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"overlay": {
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"reelPlayerOverlayRenderer": {
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"reelPlayerHeaderSupportedRenderers": {
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"reelPlayerHeaderRenderer": {
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"timestampText": {
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"simpleText": "2 days ago"
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}
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}
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}
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}
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}
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}
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},
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"thumbnail": {
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"thumbnails": [
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{
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"height": 720,
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"url": "https://i.ytimg.com/vi/glyJWxp7a5g/hq720_2.jpg?sqp=-oaymwEdCJUDENAFSFXyq4qpAw8IARUAAIhCcAHAAQbQAQE=&rs=AOn4CLCUzo9AlrNh4n4cZfTOB8_Gf5aAkw",
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"width": 405
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}
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]
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},
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"videoId": "glyJWxp7a5g",
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"viewCountText": {
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"simpleText": "593K views"
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}
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}
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}
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```
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## [3] Channel handles in search results
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- **Encountered on:** 20.11.2022
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- **Impact:** 🟡 Medium
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- **Endpoint:** search
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![A/B test 3 screenshot](./_img/ab_3.png)
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Instead of subscriber count / video count, a channel item from the search result now
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displays the channel handle and the subscriber count. The video count was removed.
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The implementation looks pretty quick and dirty, as they did not even bother to rename
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their response parameters. So this might change again in the future.
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Note that channels without handles still use the old data model, even on the same page.
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**OLD**
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```json
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{
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"subscriberCountText": {
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"accessibility": {
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"accessibilityData": {
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"label": "2.92 million subscribers"
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}
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},
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"simpleText": "2.92M subscribers"
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},
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"videoCountText": {
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"runs": [
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{
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"text": "219"
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},
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{
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"text": " videos"
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}
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]
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}
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}
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```
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**NEW**
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```json
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{
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"videoCountText": {
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"accessibility": {
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"accessibilityData": {
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"label": "4.03 million subscribers"
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}
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},
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"simpleText": "4.03M subscribers"
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},
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"subscriberCountText": {
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"simpleText": "@MusicTravelLove"
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}
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}
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```
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## [4] Video tab on the Trending page
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- **Encountered on:** 1.04.2023
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- **Impact:** 🟢 Low
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- **Endpoint:** browse (trending videos)
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YouTube moved the list of trending videos from the main _trending_ page to a separate
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tab (Videos).
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The video tab is fetched with the params `4gIOGgxtb3N0X3BvcHVsYXI%3D`.
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This new tab contains two shelves (video lists), the first one labeled "Trending videos"
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which contains the regular trends and the second one named "Recently trending".
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The data model for the video shelves did not change.
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**OLD**
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![A/B test 4 old screenshot](./_img/ab_4_old.png)
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**NEW**
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![A/B test 4 old screenshot](./_img/ab_4_new.png)
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## [5] Page header renderer on the Trending page
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- **Encountered on:** 1.05.2023
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- **Impact:** 🟢 Low
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- **Endpoint:** browse (trending videos)
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YouTube changed the header renderer type on the trending page to a `pageHeaderRenderer`.
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**OLD**
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```json
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{
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"c4TabbedHeaderRenderer": {
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"avatar": {
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"thumbnails": [
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{
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"height": 100,
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"url": "https://www.youtube.com/img/trending/avatar/trending_avatar.png",
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"width": 100
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}
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]
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},
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"title": "Trending",
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"trackingParams": "CBAQ8DsiEwiXi_iUht76AhVM6hEIHfgTB2g="
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}
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}
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```
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**NEW**
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```json
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{
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"pageHeaderRenderer": {
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"pageTitle": "Trending",
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"content": {
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"pageHeaderViewModel": {
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"title": {
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"dynamicTextViewModel": { "text": { "content": "Trending" } }
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},
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"image": {
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"contentPreviewImageViewModel": {
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"image": {
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"sources": [
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{
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"url": "https://www.youtube.com/img/trending/avatar/trending.png",
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"width": 100,
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"height": 100
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}
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]
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},
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"style": "CONTENT_PREVIEW_IMAGE_STYLE_CIRCLE"
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}
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}
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}
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}
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}
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}
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```
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## [6] New Music Discography page
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- **Encountered on:** 13.05.2023
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- **Impact:** 🟡 Medium
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- **Endpoint:** browse (music artist)
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YouTube merged the 2 sections for singles and albums on artist pages together. Now
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there is only a *Top Releases* section.
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YouTube also changed the way the full discography page is fetched, surprisingly making
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it easier for alternative clients. The discography page now has its own content ID in
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the format of `MPAD<channel id>` (Music Page Artist Discography). This page can be
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fetched with a regular browse request without requiring parameters to be parsed or a
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visitor data cookie to be set, as it was the case with the old system.
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**OLD**
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![A/B test 4 old screenshot](./_img/ab_6_old.png)
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**NEW**
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![A/B test 4 old screenshot](./_img/ab_6_new.png)
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