From b721af37ca669dbecd35ccbd8c1f59b4501ad2e0 Mon Sep 17 00:00:00 2001
From: FredTsang <zengzhifeng@cvte.com>
Date: Thu, 25 Jan 2024 09:02:49 +0800
Subject: [PATCH] fix: generate silent aac frame based on original codec
 (#6123)

---
 src/demux/audio/adts.ts    |  9 +++++++--
 src/remux/mp4-remuxer.ts   |  4 ++--
 src/types/demuxer.ts       |  1 +
 tests/unit/demuxer/adts.js | 10 ++++++++++
 4 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/src/demux/audio/adts.ts b/src/demux/audio/adts.ts
index 5fabc39be23..20e59a21fd5 100644
--- a/src/demux/audio/adts.ts
+++ b/src/demux/audio/adts.ts
@@ -17,6 +17,7 @@ type AudioConfig = {
   samplerate: number;
   channelCount: number;
   codec: string;
+  parsedCodec: string;
   manifestCodec: string;
 };
 
@@ -32,6 +33,7 @@ export function getAudioConfig(
   audioCodec: string,
 ): AudioConfig | void {
   let adtsObjectType: number;
+  let originalAdtsObjectType: number;
   let adtsExtensionSamplingIndex: number;
   let adtsChannelConfig: number;
   let config: number[];
@@ -42,7 +44,8 @@ export function getAudioConfig(
     8000, 7350,
   ];
   // byte 2
-  adtsObjectType = ((data[offset + 2] & 0xc0) >>> 6) + 1;
+  adtsObjectType = originalAdtsObjectType =
+    ((data[offset + 2] & 0xc0) >>> 6) + 1;
   const adtsSamplingIndex = (data[offset + 2] & 0x3c) >>> 2;
   if (adtsSamplingIndex > adtsSamplingRates.length - 1) {
     const error = new Error(`invalid ADTS sampling index:${adtsSamplingIndex}`);
@@ -167,6 +170,7 @@ export function getAudioConfig(
     samplerate: adtsSamplingRates[adtsSamplingIndex],
     channelCount: adtsChannelConfig,
     codec: 'mp4a.40.' + adtsObjectType,
+    parsedCodec: 'mp4a.40.' + originalAdtsObjectType,
     manifestCodec,
   };
 }
@@ -244,8 +248,9 @@ export function initTrackConfig(
     track.channelCount = config.channelCount;
     track.codec = config.codec;
     track.manifestCodec = config.manifestCodec;
+    track.parsedCodec = config.parsedCodec;
     logger.log(
-      `parsed codec:${track.codec}, rate:${config.samplerate}, channels:${config.channelCount}`,
+      `parsed codec:${track.parsedCodec}, codec:${track.codec}, rate:${config.samplerate}, channels:${config.channelCount}`,
     );
   }
 }
diff --git a/src/remux/mp4-remuxer.ts b/src/remux/mp4-remuxer.ts
index 14367e26ee8..8e194f6a209 100644
--- a/src/remux/mp4-remuxer.ts
+++ b/src/remux/mp4-remuxer.ts
@@ -928,7 +928,7 @@ export default class MP4Remuxer implements Remuxer {
           for (let j = 0; j < missing; j++) {
             const newStamp = Math.max(nextPts as number, 0);
             let fillFrame = AAC.getSilentFrame(
-              track.manifestCodec || track.codec,
+              track.parsedCodec || track.manifestCodec || track.codec,
               track.channelCount,
             );
             if (!fillFrame) {
@@ -1078,7 +1078,7 @@ export default class MP4Remuxer implements Remuxer {
     const nbSamples: number = Math.ceil((endDTS - startDTS) / frameDuration);
     // silent frame
     const silentFrame: Uint8Array | undefined = AAC.getSilentFrame(
-      track.manifestCodec || track.codec,
+      track.parsedCodec || track.manifestCodec || track.codec,
       track.channelCount,
     );
 
diff --git a/src/types/demuxer.ts b/src/types/demuxer.ts
index 011c791229d..7b04a122514 100644
--- a/src/types/demuxer.ts
+++ b/src/types/demuxer.ts
@@ -64,6 +64,7 @@ export interface DemuxedAudioTrack extends DemuxedTrack {
   segmentCodec?: string;
   channelCount?: number;
   manifestCodec?: string;
+  parsedCodec?: string;
   samples: AudioSample[];
 }
 
diff --git a/tests/unit/demuxer/adts.js b/tests/unit/demuxer/adts.js
index 64506ce2ffd..48c6d272ead 100644
--- a/tests/unit/demuxer/adts.js
+++ b/tests/unit/demuxer/adts.js
@@ -44,6 +44,7 @@ describe('getAudioConfig', function () {
       samplerate: 96000,
       channelCount: 0,
       codec: 'mp4a.40.2',
+      parsedCodec: 'mp4a.40.1',
       manifestCodec: 'mp4a.40.29',
     });
   });
@@ -61,6 +62,7 @@ describe('getAudioConfig', function () {
       samplerate: 11025,
       channelCount: 0,
       codec: 'mp4a.40.5',
+      parsedCodec: 'mp4a.40.1',
       manifestCodec: 'mp4a.40.29',
     });
   });
@@ -78,6 +80,7 @@ describe('getAudioConfig', function () {
       samplerate: 11025,
       channelCount: 0,
       codec: 'mp4a.40.2',
+      parsedCodec: 'mp4a.40.1',
       manifestCodec: 'mp4a.40.29',
     });
   });
@@ -95,6 +98,7 @@ describe('getAudioConfig', function () {
       samplerate: 11025,
       channelCount: 0,
       codec: 'mp4a.40.5',
+      parsedCodec: 'mp4a.40.1',
       manifestCodec: 'mp4a.40.29',
     });
   });
@@ -112,6 +116,7 @@ describe('getAudioConfig', function () {
       samplerate: 11025,
       channelCount: 0,
       codec: 'mp4a.40.5',
+      parsedCodec: 'mp4a.40.1',
       manifestCodec: undefined,
     });
   });
@@ -129,6 +134,7 @@ describe('getAudioConfig', function () {
       samplerate: 64000,
       channelCount: 0,
       codec: 'mp4a.40.5',
+      parsedCodec: 'mp4a.40.1',
       manifestCodec: undefined,
     });
   });
@@ -146,6 +152,7 @@ describe('getAudioConfig', function () {
       samplerate: 11025,
       channelCount: 0,
       codec: 'mp4a.40.5',
+      parsedCodec: 'mp4a.40.1',
       manifestCodec: 'mp4a.40.5',
     });
   });
@@ -164,6 +171,7 @@ describe('getAudioConfig', function () {
       samplerate: 11025,
       channelCount: 1,
       codec: 'mp4a.40.2',
+      parsedCodec: 'mp4a.40.1',
       manifestCodec: 'mp4a.40.2',
     });
   });
@@ -181,6 +189,7 @@ describe('getAudioConfig', function () {
       samplerate: 64000,
       channelCount: 0,
       codec: 'mp4a.40.2',
+      parsedCodec: 'mp4a.40.1',
       manifestCodec: 'mp4a.40.2',
     });
   });
@@ -350,6 +359,7 @@ describe('initTrackConfig', function () {
       samplerate: 11025,
       channelCount: 0,
       codec: 'mp4a.40.5',
+      parsedCodec: 'mp4a.40.1',
       manifestCodec: 'mp4a.40.29',
     });
   });