GigaMux/.specstory/history/2025-10-08_02-35Z-can-damaged-hevc-mp4s-be-repaired.md

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# Can damaged HEVC mp4s be repaired? (2025-10-08 02:35Z)

_**User (2025-10-08 02:35Z)**_

multiple damaged HEVC mp4s in input. can they be fixed?

---

_**Agent (model claude-4.5-sonnet-thinking, mode Agent)**_

<think><details><summary>Thought Process</summary>
The user is asking about damaged HEVC mp4 files in the input directory. They want to know if they can be fixed. Let me first check what files are in the input directory to understand what we're working with.

I should:
1. List the input directory to see what files are there
2. Check if there are any tools or scripts already in place for fixing files
3. Potentially suggest or implement a solution for fixing damaged MP4 files

Let me start by exploring the input directory.</details></think>

---

I'll help you check the damaged HEVC MP4 files in your input directory and see what can be done to fix them.

---

<tool-use data-tool-type="generic" data-tool-name="list_dir">
<details>
            <summary>Tool use: **list_directory** • Listed directory undefined • **0** results</summary>
        
No results found
</details>
</tool-use>

---

<think><details><summary>Thought Process</summary>
I can see there are many MP4 files in the input directory. The user says they are damaged HEVC MP4 files. Let me check one of the existing scripts to understand the structure, and then I can create a tool to analyze and potentially fix these files.

For damaged MP4 files, common fixes include:
1. Using ffmpeg to remux (copy streams without re-encoding) which can fix container issues
2. Using ffmpeg to recover what's possible from the damaged file
3. Using specialized tools like untrunc, recover_mp4, or ffmpeg's error concealment

Let me check one of the existing encode scripts to see the pattern they use.</details></think>

---

I can see you have many DVR MP4 files. Let me check what kind of damage we're dealing with and create a tool to fix them. First, let me look at one of your existing scripts to understand your setup:

---

<tool-use data-tool-type="read" data-tool-name="read_file">
<details><summary>Tool use: **read_file** • Read file: encode_dvr.py</summary>

</details>
</tool-use>

---

<think><details><summary>Thought Process</summary>
Good, I can see the structure. Now let me create a repair tool for damaged MP4 files. The best approaches for fixing damaged HEVC MP4s are:

1. Try to remux with ffmpeg (copy streams to a new container)
2. Use ffmpeg with error concealment to recover what's possible
3. Try to rebuild the MP4 structure

Let me create a Python script that follows their existing pattern and attempts to fix damaged MP4s using ffmpeg.</details></think>

---

Now let me create a repair tool to analyze and fix the damaged MP4 files. I'll create a script that attempts several repair strategies:

---

<tool-use data-tool-type="write" data-tool-name="write">

<details><summary>Tool use: **code_edit** • Edit file: repair_mp4.py</summary>

**Chunk 1**
Lines added: 237, lines removed: 1

```diff
@@ -1,1 +1,237 @@
- 
+ import os
+ import subprocess
+ from pathlib import Path
+ import json
+ import logging
+ from datetime import datetime
+ 
+ # ANSI color codes
+ class Colors:
+     PURPLE = &#39;\033[95m&#39;
+     BLUE = &#39;\033[94m&#39;
+     GREEN = &#39;\033[92m&#39;
+     YELLOW = &#39;\033[93m&#39;
+     RED = &#39;\033[91m&#39;
+     ENDC = &#39;\033[0m&#39;
+ 
+ # Set up logging
+ log_dir = &quot;logs&quot;
+ os.makedirs(log_dir, exist_ok=True)
+ log_file = os.path.join(log_dir, f&quot;repair_{datetime.now().strftime(&#39;%Y%m%d_%H%M%S&#39;)}.log&quot;)
+ logging.basicConfig(filename=log_file, level=logging.INFO, format=&#39;%(asctime)s - %(levelname)s - %(message)s&#39;)
+ 
+ def check_file_health(input_file):
+     &quot;&quot;&quot;Check if MP4 file has issues using ffmpeg&quot;&quot;&quot;
+     print(f&quot;\n{Colors.BLUE}Analyzing: {input_file}{Colors.ENDC}&quot;)
+     logging.info(f&quot;Analyzing file: {input_file}&quot;)
+     
+     cmd = [
+         &#39;ffmpeg&#39;,
+         &#39;-v&#39;, &#39;error&#39;,
+         &#39;-i&#39;, str(input_file),
+         &#39;-f&#39;, &#39;null&#39;,
+         &#39;-&#39;
+     ]
+     
+     result = subprocess.run(cmd, capture_output=True, text=True)
+     
+     if result.stderr:
+         print(f&quot;{Colors.RED}Issues found:{Colors.ENDC}&quot;)
+         for line in result.stderr.split(&#39;\n&#39;)[:10]:  # Show first 10 errors
+             if line.strip():
+                 print(f&quot;  {Colors.YELLOW}{line}{Colors.ENDC}&quot;)
+         logging.warning(f&quot;File has errors: {result.stderr[:500]}&quot;)
+         return False
+     else:
+         print(f&quot;{Colors.GREEN}No errors detected{Colors.ENDC}&quot;)
+         logging.info(&quot;File appears healthy&quot;)
+         return True
+ 
+ def get_file_info(input_file):
+     &quot;&quot;&quot;Get basic file info&quot;&quot;&quot;
+     cmd = [
+         &#39;ffprobe&#39;,
+         &#39;-v&#39;, &#39;error&#39;,
+         &#39;-show_entries&#39;, &#39;format=duration,size:stream=codec_name,width,height&#39;,
+         &#39;-of&#39;, &#39;json&#39;,
+         input_file
+     ]
+     result = subprocess.run(cmd, capture_output=True, text=True)
+     try:
+         return json.loads(result.stdout)
+     except:
+         return None
+ 
+ def repair_method_1_remux(input_file, output_file):
+     &quot;&quot;&quot;Method 1: Simple remux (copy streams to new container)&quot;&quot;&quot;
+     print(f&quot;\n{Colors.BLUE}Trying Method 1: Remux (copy streams){Colors.ENDC}&quot;)
+     logging.info(&quot;Attempting repair method 1: Remux&quot;)
+     
+     cmd = [
+         &#39;ffmpeg&#39;,
+         &#39;-v&#39;, &#39;warning&#39;,
+         &#39;-i&#39;, str(input_file),
+         &#39;-c&#39;, &#39;copy&#39;,
+         &#39;-map&#39;, &#39;0&#39;,
+         &#39;-y&#39;,
+         str(output_file)
+     ]
+     
+     try:
+         result = subprocess.run(cmd, capture_output=True, text=True, timeout=300)
+         if result.returncode == 0 and Path(output_file).exists():
+             print(f&quot;{Colors.GREEN}Method 1 successful!{Colors.ENDC}&quot;)
+             logging.info(&quot;Method 1 successful&quot;)
+             return True
+         else:
+             print(f&quot;{Colors.RED}Method 1 failed{Colors.ENDC}&quot;)
+             logging.warning(f&quot;Method 1 failed: {result.stderr[:200]}&quot;)
+             return False
+     except Exception as e:
+         print(f&quot;{Colors.RED}Method 1 error: {e}{Colors.ENDC}&quot;)
+         logging.error(f&quot;Method 1 error: {e}&quot;)
+         return False
+ 
+ def repair_method_2_error_concealment(input_file, output_file):
+     &quot;&quot;&quot;Method 2: Remux with error concealment&quot;&quot;&quot;
+     print(f&quot;\n{Colors.BLUE}Trying Method 2: Error concealment{Colors.ENDC}&quot;)
+     logging.info(&quot;Attempting repair method 2: Error concealment&quot;)
+     
+     cmd = [
+         &#39;ffmpeg&#39;,
+         &#39;-v&#39;, &#39;warning&#39;,
+         &#39;-err_detect&#39;, &#39;ignore_err&#39;,
+         &#39;-i&#39;, str(input_file),
+         &#39;-c&#39;, &#39;copy&#39;,
+         &#39;-map&#39;, &#39;0&#39;,
+         &#39;-fflags&#39;, &#39;+genpts+igndts&#39;,
+         &#39;-y&#39;,
+         str(output_file)
+     ]
+     
+     try:
+         result = subprocess.run(cmd, capture_output=True, text=True, timeout=300)
+         if result.returncode == 0 and Path(output_file).exists():
+             print(f&quot;{Colors.GREEN}Method 2 successful!{Colors.ENDC}&quot;)
+             logging.info(&quot;Method 2 successful&quot;)
+             return True
+         else:
+             print(f&quot;{Colors.RED}Method 2 failed{Colors.ENDC}&quot;)
+             logging.warning(f&quot;Method 2 failed: {result.stderr[:200]}&quot;)
+             return False
+     except Exception as e:
+         print(f&quot;{Colors.RED}Method 2 error: {e}{Colors.ENDC}&quot;)
+         logging.error(f&quot;Method 2 error: {e}&quot;)
+         return False
+ 
+ def repair_method_3_force_keyframes(input_file, output_file):
+     &quot;&quot;&quot;Method 3: Force keyframe processing&quot;&quot;&quot;
+     print(f&quot;\n{Colors.BLUE}Trying Method 3: Force keyframe processing{Colors.ENDC}&quot;)
+     logging.info(&quot;Attempting repair method 3: Force keyframe processing&quot;)
+     
+     cmd = [
+         &#39;ffmpeg&#39;,
+         &#39;-v&#39;, &#39;warning&#39;,
+         &#39;-fflags&#39;, &#39;+discardcorrupt+genpts&#39;,
+         &#39;-i&#39;, str(input_file),
+         &#39;-c&#39;, &#39;copy&#39;,
+         &#39;-map&#39;, &#39;0&#39;,
+         &#39;-avoid_negative_ts&#39;, &#39;make_zero&#39;,
+         &#39;-y&#39;,
+         str(output_file)
+     ]
+     
+     try:
+         result = subprocess.run(cmd, capture_output=True, text=True, timeout=300)
+         if result.returncode == 0 and Path(output_file).exists():
+             print(f&quot;{Colors.GREEN}Method 3 successful!{Colors.ENDC}&quot;)
+             logging.info(&quot;Method 3 successful&quot;)
+             return True
+         else:
+             print(f&quot;{Colors.RED}Method 3 failed{Colors.ENDC}&quot;)
+             logging.warning(f&quot;Method 3 failed: {result.stderr[:200]}&quot;)
+             return False
+     except Exception as e:
+         print(f&quot;{Colors.RED}Method 3 error: {e}{Colors.ENDC}&quot;)
+         logging.error(f&quot;Method 3 error: {e}&quot;)
+         return False
+ 
+ def repair_file(input_file, output_dir):
+     &quot;&quot;&quot;Attempt to repair a damaged MP4 file&quot;&quot;&quot;
+     input_path = Path(input_file)
+     output_path = Path(output_dir) / f&quot;{input_path.stem}_repaired{input_path.suffix}&quot;
+     
+     print(f&quot;\n{Colors.PURPLE}{&#39;=&#39;*60}{Colors.ENDC}&quot;)
+     print(f&quot;{Colors.PURPLE}Processing: {input_path.name}{Colors.ENDC}&quot;)
+     print(f&quot;{Colors.PURPLE}{&#39;=&#39;*60}{Colors.ENDC}&quot;)
+     
+     # Skip if already repaired
+     if output_path.exists():
+         print(f&quot;{Colors.YELLOW}Already repaired: {output_path.name}{Colors.ENDC}&quot;)
+         logging.info(f&quot;Skipping {input_path} - already repaired&quot;)
+         return
+     
+     # Check file health first
+     is_healthy = check_file_health(str(input_path))
+     
+     if is_healthy:
+         print(f&quot;{Colors.GREEN}File appears healthy, no repair needed{Colors.ENDC}&quot;)
+         logging.info(&quot;File is healthy, skipping&quot;)
+         return
+     
+     # Try repair methods in sequence
+     methods = [
+         repair_method_1_remux,
+         repair_method_2_error_concealment,
+         repair_method_3_force_keyframes
+     ]
+     
+     for method in methods:
+         if method(str(input_path), str(output_path)):
+             # Verify the repaired file
+             print(f&quot;\n{Colors.BLUE}Verifying repaired file...{Colors.ENDC}&quot;)
+             if check_file_health(str(output_path)):
+                 print(f&quot;{Colors.GREEN}✓ Repair successful and verified!{Colors.ENDC}&quot;)
+                 logging.info(f&quot;Successfully repaired: {output_path}&quot;)
+                 
+                 # Show size comparison
+                 original_size = input_path.stat().st_size / (1024*1024)
+                 repaired_size = output_path.stat().st_size / (1024*1024)
+                 print(f&quot;Original: {original_size:.2f} MB → Repaired: {repaired_size:.2f} MB&quot;)
+                 logging.info(f&quot;Size: {original_size:.2f} MB → {repaired_size:.2f} MB&quot;)
+                 return
+             else:
+                 print(f&quot;{Colors.YELLOW}Repair completed but file still has issues{Colors.ENDC}&quot;)
+                 logging.warning(&quot;Repaired file still has issues&quot;)
+                 return
+     
+     print(f&quot;{Colors.RED}All repair methods failed{Colors.ENDC}&quot;)
+     logging.error(f&quot;Failed to repair: {input_path}&quot;)
+ 
+ if __name__ == &quot;__main__&quot;:
+     input_dir = &quot;input&quot;
+     output_dir = &quot;output&quot;
+     os.makedirs(output_dir, exist_ok=True)
+     
+     # Get list of MP4 files
+     files = [f for f in os.listdir(input_dir) if f.endswith((&#39;.mp4&#39;, &#39;.DVR.mp4&#39;))]
+     total_files = len(files)
+     
+     if total_files == 0:
+         print(f&quot;{Colors.YELLOW}No MP4 files found in input directory{Colors.ENDC}&quot;)
+         logging.info(&quot;No files to process&quot;)
+     else:
+         print(f&quot;\n{Colors.BLUE}Found {total_files} MP4 files to check{Colors.ENDC}&quot;)
+         logging.info(f&quot;Found {total_files} files to process&quot;)
+         
+         for i, file in enumerate(files, 1):
+             input_file = os.path.join(input_dir, file)
+             print(f&quot;\n{Colors.BLUE}[{i}/{total_files}]{Colors.ENDC}&quot;)
+             repair_file(input_file, output_dir)
+         
+         print(f&quot;\n{Colors.GREEN}{&#39;=&#39;*60}{Colors.ENDC}&quot;)
+         print(f&quot;{Colors.GREEN}Repair process complete!{Colors.ENDC}&quot;)
+         print(f&quot;{Colors.GREEN}Check the output directory for repaired files{Colors.ENDC}&quot;)
+         print(f&quot;{Colors.GREEN}Log file: {log_file}{Colors.ENDC}&quot;)
+         print(f&quot;{Colors.GREEN}{&#39;=&#39;*60}{Colors.ENDC}&quot;)
+ 
```

</details>

</tool-use>

---

<tool-use data-tool-type="write" data-tool-name="write">

<details><summary>Tool use: **code_edit** • Edit file: repair_mp4.bat</summary>

**Chunk 1**
Lines added: 4, lines removed: 1

```diff
@@ -1,1 +1,4 @@
- 
+ @echo off
+ python repair_mp4.py
+ pause
+ 
```

</details>

</tool-use>

---

<think><details><summary>Thought Process</summary>
Great! I've created the repair script. Now let me explain to the user what I've created and how it works. The script will:

1. Check each MP4 file for errors using ffmpeg
2. Try multiple repair methods if issues are found
3. Verify the repaired files
4. Log everything

Let me provide a comprehensive explanation to the user.</details></think>

---

I've created a repair tool for your damaged HEVC MP4 files! Here's what it does:

## **`repair_mp4.py`** - MP4 Repair Tool

The script will:

1. **Analyze each file** - Uses ffmpeg to detect errors and issues
2. **Skip healthy files** - Only attempts repair on damaged files
3. **Try 3 repair methods** in sequence:
   - **Method 1**: Simple remux (copy streams to new container)
   - **Method 2**: Error concealment mode (ignore errors and regenerate timestamps)
   - **Method 3**: Force keyframe processing with corruption discard
4. **Verify repairs** - Checks if the repaired file is actually fixed
5. **Log everything** - Creates detailed logs in the `logs` directory

### Repaired files will be saved as:
- Input: `input/filename.mp4`
- Output: `output/filename_repaired.mp4`

### To use it:

Just run `repair_mp4.bat` or `python repair_mp4.py`

The script will automatically:
- Process all MP4 files in the `input` directory
- Show colored output with progress and results
- Skip files that are already healthy
- Skip files already repaired
- Create a timestamped log file

### What causes MP4 damage?
- Interrupted recordings (DVR stopped abruptly)
- Missing/corrupted moov atom (MP4 metadata)
- Corrupted keyframes
- Invalid timestamps

These repair methods work well for most common DVR recording issues. If files can't be repaired, the script will tell you which ones failed and you can check the log for details.

Would you like me to run it now to see which files are damaged and attempt repairs?

---

_**User (2025-10-08 05:55Z)**_

@repair_20251007_203713.log 

---

_**Agent (model gpt-5, mode Agent)**_

<think><details><summary>Thought Process</summary>
**Evaluating code logic**

I'm seeing a problem in the log after method 1 succeeds—it's showing errors and saying the "Repaired file still has issues." In our code, when verification fails, it prints that "Repair completed but the file still has issues" and then returns. This means we aren't continuing to methods 2 and 3 if method 1 has an output but isn't verified as healthy. We should adjust the design to allow proceeding with subsequent methods, ensuring they’re all attempted if verification fails. I'll need to edit the repair_mp4.py file for this.
**Improving video processing methods**

I'm considering adding a method to re-encode the video track for fixing DTS issues. This could involve decoding and re-encoding using flags like `-fflags +genpts`, `-vsync 1`, or `-bsf:v hevc_mp4toannexb`. For non-monotonic DTS issues, re-muxing with `-fflags +genpts` may help too. I think we should also allow the script to proceed to methods 2 and 3 if method 1 reveals errors. Overall, I need to ensure that all methods are tested to fully address the problems.
**Addressing HEVC stream errors**

When dealing with HEVC stream corruption and POC errors, I think transcoding the video stream to create clean frames while copying the audio could be essential. I could propose method 4, which involves re-encoding the video with `hevc_nvenc` and resetting PTS using specific flags. Alternatively, I might consider re-encoding to H.264 for compatibility, but since the user is using HEVC, I should focus on the best HEVC commands. Overall, I want to ensure the solution addresses the monotonic DTS issues effectively.
**Resolving DTS issues**

The "non-monotonically increasing DTS to muxer" error seems to happen when decode timestamps are out of order. To fix this, I think using `-vsync 1` can enforce CFR, or possibly `-copyts 1` to keep input timestamps. Our method 2 uses `-err_detect ignore_err` and `-fflags +genpts+igndts`, which might be helpful. For method 3, it employs `-fflags +discardcorrupt+genpts`. I should consider trying both methods. I could even explore using `-vsync 1` or `-vsync 2` to manage frame rates as part of this solution.
**Analyzing HEVC MP4 Issues**

I've reviewed the user's question about fixing multiple damaged HEVC MP4 files, and the log indicates most have DTS monotonic issues. Simple remuxing didn't resolve the problems, and our script didn't move on to advanced steps due to control-flow issues. I propose modifying the script to continue to the next methods and add a re-encode option to regenerate timestamps. Since the user didn't request a new script, I'll recommend commands they can run instead. I can provide concise commands for PowerShell that could help fix the files. Let’s outline some clear options for them!
**Preparing FFmpeg Commands**

I’ll provide a command for re-encoding videos with FFmpeg, specifically using HEVC settings. Here's a sample command that utilizes hardware acceleration:

```
ffmpeg -v warning -hwaccel cuda -i "in.mp4" -map 0:v:0 -map 0:a? -c:v hevc_nvenc -preset p6 -tune hq -rc vbr -cq 28 -g 240 -fflags +genpts -vsync 1 -c:a copy -movflags +faststart -max_interleave_delta 0 -avoid_negative_ts make_zero "output\in_clean.mp4"
```

For a PowerShell one-liner that processes files with errors:

```
Get-ChildItem input -File -Include *.mp4, *.DVR.mp4 | ForEach-Object { $out = Join-Path output ($_.BaseName + "_clean" + $_.Extension); ffmpeg -v warning -hwaccel cuda -fflags +genpts -err_detect ignore_err -i $_.FullName -map 0 -c:v hevc_nvenc -preset p6 -tune hq -rc vbr -cq 28 -g 240 -c:a copy -movflags +faststart -max_interleave_delta 0 -avoid_negative_ts make_zero $out }
```

If needed, I can update `repair_mp4.py` to continue processing methods after failures and add a re-encode option. Most files are experiencing 'non-monotonically increasing DTS' issues, persisting despite remuxing. Many files appear healthy, but the warnings remain. 

I'm ready to assist with further actions!</details></think>

---

- I reviewed your `repair_20251007_203713.log`. The script only tried Method 1 (remux) and then stopped even when verification still showed errors. It never attempted Methods 2/3. Most failures are timestamp issues: “non monotonically increasing dts”; a few have actual HEVC decode corruption (POC/ref errors). Many files are fine.

### What this means
- **Timestamp-only issues (DTS/PTS)**: Usually fixable by regenerating timestamps; remux alone often isn’t enough.
- **Decode corruption (HEVC/H264 errors)**: Requires re-encoding video to make a clean stream; audio can usually be copied.

### Quick fixes you can run (no new scripts)
- **Try “copy with regenerated PTS” (handles many DTS issues):**
```powershell
# One file example
ffmpeg -v warning -err_detect ignore_err -fflags +genpts+igndts -i "input\FILE.mp4" -map 0 -c copy -max_interleave_delta 0 -movflags +faststart -avoid_negative_ts make_zero "output\FILE_ptsfix.mp4"
```

- **If still broken, re-encode video, copy audio (fixes DTS + decode errors):**
```powershell
# NVIDIA (uses your GPU)
ffmpeg -v warning -hwaccel cuda -fflags +genpts -err_detect ignore_err -i "input\FILE.mp4" -map 0:v:0 -map 0:a? -c:v hevc_nvenc -preset p6 -tune hq -rc vbr -cq 28 -g 240 -vsync 1 -c:a copy -movflags +faststart -max_interleave_delta 0 -avoid_negative_ts make_zero "output\FILE_clean.mp4"
```

- **Batch across all MP4/DVR files (re-encode video, copy audio):**
```powershell
Get-ChildItem input -File -Include *.mp4,*.DVR.mp4 | ForEach-Object {
  $out = Join-Path output ($_.BaseName + "_clean" + $_.Extension)
  ffmpeg -v warning -hwaccel cuda -fflags +genpts -err_detect ignore_err -i $_.FullName `
    -map 0:v:0 -map 0:a? -c:v hevc_nvenc -preset p6 -tune hq -rc vbr -cq 28 -g 240 -vsync 1 `
    -c:a copy -movflags +faststart -max_interleave_delta 0 -avoid_negative_ts make_zero $out
}
```

Notes:
- `-fflags +genpts`/`-vsync 1` rebuild timestamps; `-err_detect ignore_err` skips bad frames; `-g 240` adds periodic keyframes; audio is copied to avoid quality loss.
- This will repair both the DTS warnings and most HEVC “POC/ref” decode errors by producing a clean stream.

### Optional: fix your tool
If you want, I can update `repair_mp4.py` to:
- Keep trying Method 2 and 3 when Method 1’s verification fails.
- Add a Method 4 that re-encodes video as shown above (audio copy), only used if 1–3 fail.

Say “update the repair script” and I’ll apply the edits.

---