Function extractFLV

src/core/lib/FileSignatures.mjs:3313–3350

(bytes, offset)

 * @returns {Uint8Array}
 */
export function extractFLV(bytes, offset) {
    const stream = new Stream(bytes.slice(offset));

    // Move past signature, version and flags
    stream.moveForwardsBy(5);

    // Read header size
    const headerSize = stream.readInt(4, "be");

    // Skip through the rest of the header
    stream.moveForwardsBy(headerSize - 9);

    let tagSize = -11; // Fake size of previous tag header
    while (stream.hasMore()) {
        const prevTagSize = stream.readInt(4, "be");
        const tagType = stream.readInt(1);

        if ([8, 9, 18].indexOf(tagType) < 0) {
            // This tag is not valid
            stream.moveBackwardsBy(1);
            break;
        }

        if (prevTagSize !== (tagSize + 11)) {
            // Previous tag was not valid, reverse back over this header
            // and the previous tag body and header
            stream.moveBackwardsBy(tagSize + 11 + 5);
            break;
        }

        tagSize = stream.readInt(3, "be");

        // Move past the rest of the tag header and payload
        stream.moveForwardsBy(7 + tagSize);
    }

    return stream.carve();
}


/**