fix(mp4-tools): set default color descriptions to satisfy Firefox

In Firefox either you omit the chroma values, or you have to complete the rest of the color descriptions.

Otherwise even the most basic AV1 Main 4:2:0 8-bit video will be reported as unsupported
in HTMLMediaElement.canPlayType and MediaSource.isTypeSupported. Chromium is not affected by this.

Signed-off-by: nyanmisaka <nst799610810@gmail.com>

src/utils/mp4-tools.ts

@@ -369,6 +369,12 @@ function parseStsd(stsd: Uint8Array): { codec: string; encrypted: boolean } {
       const chromaSubsamplingX = (av1CBox[2] & 0x08) >> 3;
       const chromaSubsamplingY = (av1CBox[2] & 0x04) >> 2;
       const chromaSamplePosition = av1CBox[2] & 0x03;
+      // TODO: parse color_description_present_flag
+      // default it to BT.709/limited range for now
+      const colorPrimaries = 1;
+      const transferCharacteristics = 1;
+      const matrixCoefficients = 1;
+      const videoFullRangeFlag = 0;
       codec +=
         '.' +
         profile +
@@ -382,7 +388,15 @@ function parseStsd(stsd: Uint8Array): { codec: string; encrypted: boolean } {
         '.' +
         chromaSubsamplingX +
         chromaSubsamplingY +
-        chromaSamplePosition;
+        chromaSamplePosition +
+        '.' +
+        addLeadingZero(colorPrimaries) +
+        '.' +
+        addLeadingZero(transferCharacteristics) +
+        '.' +
+        addLeadingZero(matrixCoefficients) +
+        '.' +
+        videoFullRangeFlag;
       break;
     }
     case 'ac-3':