fix(codec) Always use DD when its supported by Jicofo and browser.

The bridge is now able to use DD headers for VP8 and VP9 as well so there is no need to remove it from remote desc when the call switches from AV1 to VP8/VP9.

modules/RTC/TPCUtils.js

@@ -18,9 +18,6 @@ import browser from '../browser';
 import SDPUtil from '../sdp/SDPUtil';
 
 const logger = getLogger('modules/RTC/TPCUtils');
-const DD_HEADER_EXT_URI
-    = 'https://aomediacodec.github.io/av1-rtp-spec/#dependency-descriptor-rtp-header-extension';
-const DD_HEADER_EXT_ID = 11;
 const VIDEO_CODECS = [ CodecMimeType.AV1, CodecMimeType.H264, CodecMimeType.VP8, CodecMimeType.VP9 ];
 
 /**
@@ -921,53 +918,4 @@ export class TPCUtils {
 
         return mungedSdp;
     }
-
-    /**
-     * Checks if the AV1 Dependency descriptors are negotiated on the bridge peerconnection and removes them from the
-     * SDP when codec selected is VP8 or VP9.
-     *
-     * @param {transform.SessionDescription} parsedSdp that needs to be munged.
-     * @returns {string} the munged SDP.
-     */
-    updateAv1DdHeaders(parsedSdp) {
-        if (!browser.supportsDDExtHeaders()) {
-            return parsedSdp;
-        }
-        const mungedSdp = parsedSdp;
-        const mLines = mungedSdp.media.filter(m => m.type === MediaType.VIDEO);
-
-        mLines.forEach((mLine, idx) => {
-            const senderMids = Array.from(this.pc.localTrackTransceiverMids.values());
-            const isSender = senderMids.length
-                ? senderMids.find(mid => mLine.mid.toString() === mid.toString())
-                : idx === 0;
-            const payload = mLine.payloads.split(' ')[0];
-            let { codec } = mLine.rtp.find(rtp => rtp.payload === Number(payload));
-
-            codec = codec.toLowerCase();
-
-            if (isSender && mLine.ext?.length) {
-                const headerIndex = mLine.ext.findIndex(ext => ext.uri === DD_HEADER_EXT_URI);
-                const shouldNegotiateHeaderExts = codec === CodecMimeType.AV1 || codec === CodecMimeType.H264
-
-                    // Removing DD ext header lines from the sdp breaks the scalability for FF with version 136+.
-                    || (codec === CodecMimeType.VP8 && browser.isFirefox());
-
-                if (!this.supportsDDHeaderExt && headerIndex >= 0) {
-                    this.supportsDDHeaderExt = true;
-                }
-
-                if (this.supportsDDHeaderExt && shouldNegotiateHeaderExts && headerIndex < 0) {
-                    mLine.ext.push({
-                        value: DD_HEADER_EXT_ID,
-                        uri: DD_HEADER_EXT_URI
-                    });
-                } else if (!shouldNegotiateHeaderExts && headerIndex >= 0) {
-                    mLine.ext.splice(headerIndex, 1);
-                }
-            }
-        });
-
-        return mungedSdp;
-    }
 }

modules/RTC/TraceablePeerConnection.js

@@ -1971,7 +1971,6 @@ TraceablePeerConnection.prototype._mungeDescription = function(description) {
     mungedSdp = this.tpcUtils.mungeOpus(mungedSdp);
     mungedSdp = this.tpcUtils.mungeCodecOrder(mungedSdp);
     mungedSdp = this.tpcUtils.setMaxBitrates(mungedSdp, true);
-    mungedSdp = this.tpcUtils.updateAv1DdHeaders(mungedSdp);
     const mungedDescription = {
         type: description.type,
         sdp: transform.write(mungedSdp)

modules/qualitycontrol/CodecSelection.js

@@ -71,37 +71,24 @@ export class CodecSelection {
                 }
             }
 
-            // Push VP9 to the end of the list so that the client continues to decode VP9 even if its not
-            // preferable to encode VP9 (because of browser bugs on the encoding side or other reasons).
+            // Push AV1 and VP9 to the end of the list if they are supported by the browser but has implementation bugs
+            // For example, 136 and newer versions of Firefox supports AV1 but only simulcast and not SVC. Even with
+            // simulcast, temporal scalability is not supported. This way Firefox will continue to decode AV1 from
+            // other endpoints but will use VP8 for encoding. Similar issues exist with VP9 on Safari and Firefox.
             const isVp9EncodeSupported = browser.supportsVP9() || (browser.isWebKitBased() && connectionType === 'p2p');
 
-            if (!isVp9EncodeSupported) {
-                const index = selectedOrder.findIndex(codec => codec === CodecMimeType.VP9);
+            [ CodecMimeType.AV1, CodecMimeType.VP9 ].forEach(codec => {
+                if ((codec === CodecMimeType.AV1 && browser.isFirefox() && !enableAV1ForFF)
+                    || (codec === CodecMimeType.VP9 && !isVp9EncodeSupported)) {
+                    const index = selectedOrder.findIndex(selectedCodec => selectedCodec === codec);
 
-                if (index !== -1) {
-                    selectedOrder.splice(index, 1);
+                    if (index !== -1) {
+                        selectedOrder.splice(index, 1);
 
-                    // Remove VP9 from the list when E2EE is enabled since it is not supported.
-                    // TODO - remove this check when support for VP9-E2EE is introduced.
-                    if (!this.conference.isE2EEEnabled()) {
-                        selectedOrder.push(CodecMimeType.VP9);
+                        selectedOrder.push(codec);
                     }
                 }
-            }
-
-            // Adding this flag for testing purposes since AV1 is not properly supported by FF (it doesn't support SVC
-            // and it doesn't send temporal layers with simulcast).
-            if (browser.isFirefox() && !enableAV1ForFF) {
-                // By default moving AV1 to the end of the list. This way AV1 won't be used for encoding but can be
-                // used for decoding.
-                const index = selectedOrder.findIndex(codec => codec === CodecMimeType.AV1);
-
-                if (index !== -1) {
-                    selectedOrder.splice(index, 1);
-
-                    selectedOrder.push(CodecMimeType.AV1);
-                }
-            }
+            });
 
             logger.info(`Codec preference order for ${connectionType} connection is ${selectedOrder}`);
             this.codecPreferenceOrder[connectionType] = selectedOrder;