# DASH encoding failing

**URL:** <https://community.bitmovin.com/t/dash-encoding-failing/3130>\
**Category:** Support\
**Created:** [July 22, 2024, 5:44pm UTC](https://community.bitmovin.com/t/dash-encoding-failing/3130 "2024-07-22T17:44:05Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![nomad-cms](https://avatars.discourse-cdn.com/v4/letter/n/97f17d/32.png) [@nomad-cms](https://community.bitmovin.com/u/nomad-cms)\
**Post date:** [July 22, 2024, 5:44pm UTC](https://community.bitmovin.com/t/dash-encoding-failing/3130/1 "2024-07-22T17:44:05Z")

</div>

### Product

Encoding - VOD

### Question

Unable to encode to dash format  
encodingid: 2be682be-3f37-44e6-8648-7e437c1f8d1a

Encoding has failed.

Problem with processing input.

Encoding on cluster failed.

Error acquiring encoding instance. Encoding continues

An error occurred during audio transcoding.

---

<div class="post-metadata">

**Author:** ![kazuhide](https://sea1.discourse-cdn.com/flex015/user_avatar/community.bitmovin.com/kazuhide/32/263_2.png) [@kazuhide](https://community.bitmovin.com/u/kazuhide)\
**Post date:** [July 23, 2024, 1:24am UTC](https://community.bitmovin.com/t/dash-encoding-failing/3130/2 "2024-07-23T01:24:03Z")

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Hi,

Thank you for reaching out to the Bitmovin Community.

After reviewing the logs and settings of the encoding job, the error seems to be caused by the `PTSAlignMode.ALIGN_ZERO_NEGATIVE_CTO` being set for fMP4 muxing of the audio. Specifically, the error was caused by the PTSAlignMode setting in the following Fmp4 muxing:

```auto
  "type": "FMP4",
  "id": "33e3ff08-4b45-4e8c-826b-5ef1182983bb",
  "streams": [
    {
      "id": "5147687f-7e0b-4e48-a463-a7d476e89223",
      "name": "NOMAD_AAC_128K",
      "inputStreams": [...],
      "codecConfigId": "55429d90-c640-4d41-8141-c0de310f0048",
      "codecConfig": {
        "id": "55429d90-c640-4d41-8141-c0de310f0048",
        "name": "NOMAD_AAC_128K",
        "type": "AAC",
        "bitrate": 256000,
        "rate": 44100,
        "cutoffFrequency": 10000,
        "channelLayout": "NONE"
      }
    }
  ],
  "streamConditionsMode": "DROP_MUXING",
  "name": "AAC_128K_FMP4",
  "segmentLength": 4,
  "segmentNaming": "weekendupdate_lite_DASH_1080_%number%.mp4",
  "initSegmentName": "weekendupdate_lite_DASH_1080_INIT.mp4",
  "ptsAlignMode": "ALIGN_ZERO_NEGATIVE_CTO"

```

This mode is a valid option when setting fMP4 for H.264 and H.265, but it can’t be used for other codecs such as AAC audio as noted in the release note ([link](https://developer.bitmovin.com/encoding/docs/rest-api-services-11000-11500#11000)).

Therefore, could you please try removing the PTSAlignMode setting from the above audio fMP4 muxing configuration and attempt the encoding again? Please let us know if you have any question. Thank you.

Best Regards,  
Kazuhide

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<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/flex015/uploads/bitmovin/original/1X/1ab86334145095b0af9c5b924fa3ae6d920b6482.png) [@system](https://community.bitmovin.com/u/system)\
**Post date:** [July 23, 2024, 12:23pm UTC](https://community.bitmovin.com/t/dash-encoding-failing/3130/3 "2024-07-23T12:23:20Z")

</div>

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