Solutions¶

Here on this page is listed information about possible solutions that can be used to fix validation errors.

The suggested solutions are in continuous development and using them should be carefully considered beforehand.

Migrations ¶

Migrate audio stream from WMA file to WAVE format ¶

The suggestion¶

Migrate WMA file to WAVE format using FFmpeg with default settings.

Execution¶

ffmpeg -i <input file>.wma <output file>.wav

Tested with: FFmpeg 6.0

Effects¶

Without other parameters than the input/output arguments FFmpeg selects automatically stream from the input file for migration.

The automatic selection is described in FFmpeg’s documentation: https://ffmpeg.org/ffmpeg.html#Automatic-stream-selection

Justification¶

The input file has single audio stream.

Migrated files¶

File format	Version	Specification	Description	Location
audio/x-wav	(:unap)		The file is migrated from invalid__wma7.wma using Migrate audio stream from WMA file to WAVE format	corpus
audio/x-wav	(:unap)		The file is migrated from valid__wma9.wma using Migrate audio stream from WMA file to WAVE format	corpus

Remove album cover image from MP3 file ¶

The suggestion¶

Migrate only audio streams from an MP3 file to remove an attached image and related video container stream.

Execution¶

ffmpeg -i <input file>.mp3 -c:a copy -map 0 <output file>.mp3

Tested with: FFmpeg 6.0

Effects¶

Image and videocontainer streams are stripped from the output file. Only (all) audio streams are migrated to the output file.

Justification¶

MP3 files contain primarily audio.

Migrated files¶

None found

Migrate MPO file to JPEG format ¶

The suggestion¶

A valid JPEG file can be created from a MPO file that contains images that complement the first otherwise valid JPEG file by removing the extra images from the file.

Execution¶

exiftool -MPF:All= -Trailer:All= -overwrite_original <input>.JPG

Tested with:

Effects¶

The main image and its headers stay unchanged. Additional images, such as a preview image and its APP2 header section, are removed. The -overwrite_original switch makes ExifTool to overwrite the input file.

Justification¶

MPO file format is extension of JPEG for saving multiple images into a same file.

Migrated files¶

None found

Migrate Apple ProRes file to FFV1 and FLAC streams in MKV container ¶

The suggestion¶

All video and audio streams and the first subtitle stream are migrated into a MKV container as FFV1 video streams and FLAC audio streams. The subtitle stream is migrated as it is. The Matroska MKV container supports video, audio and subtitle streams.

Execution¶

ffmpeg -i <input.mov> -map 0:v -map 0:a -c:v ffv1 -level 3 -g 1 -slicecrc 1 -context 1 -c:a flac -c:s copy <output.mkv>

Tested with: FFmpeg 6.0

Effects¶

Video and audio streams and the first subtitle stream are migrated.

-map 0:v and -map 0:a select every video and audio stream from the input file. -c:v ffv1 and -c:a flac set FFV1 and FLAC codecs for video and audio encoding. -c:s copy copies the subtitle stream.

-level, -g, -slicecrc and -context are both general and codec-specific parameters for the encoding with FFV1 codec. Using them does not alter stream hashes from video streams: https://amiaopensource.github.io/ffmprovisr/#get_streamhash. AAC audio hashes change in the migration.

All of the following parameters for the FFV1 codec are not fully documented:

-level 3 sets encoding to FFV1 version 3 (1.3): https://www.rfc-editor.org/rfc/rfc9043#name-introduction. Earlier versions seem to be disabled at the moment in FFmpeg.

-g 1 sets interval for keyframes (group of frames) so that every frame is a keyframe: https://git.ffmpeg.org/gitweb/ffmpeg.git/blob/refs/heads/release/6.0:/libavcodec/options_table.h#l93.

-slicecrc 1 turns on error detection for FFV1 slices used in FFV1 frames: https://git.ffmpeg.org/gitweb/ffmpeg.git/blob/refs/heads/release/6.0:/libavcodec/ffv1enc.c#l1243.

-context 1 sets bigger (rather than smaller 0) ring size for FFV1 algorithm.

Codec-specfic parameters have descriptions in FFmpeg’s documentation at https://ffmpeg.org/ffmpeg-codecs.html#Codec-Options. Rewrapping MOV container to MKV follows ffmprovisr’s method for video and audio streams: https://amiaopensource.github.io/ffmprovisr/#basic-rewrap. Modification of video and audio bitsreams can be detected by FFmpeg’s stream hashing functionality: https://amiaopensource.github.io/ffmprovisr/#get_stream_checksum.

Justification¶

Raw video, audio and subtitle outputs for playback are not modified.

Migrated files¶

File format	Version	Specification	Description	Location
video/x-matroska	4	RFC, matroska.org	The file is migration from invalid__cinepak_lpcm8.mov using Migrate Apple ProRes file to FFV1 and FLAC streams in MKV container. An unsupported plain data stream was removed in migration.	corpus
video/x-matroska	4	RFC, matroska.org	The file is migration from invalid__prores_lpcm8.mov using Migrate Apple ProRes file to FFV1 and FLAC streams in MKV container. An unsupported plain data stream was removed in migration.	corpus
video/x-matroska	4	RFC, matroska.org	The file is migration from valid__dv_lpcm8.mov using Migrate Apple ProRes file to FFV1 and FLAC streams in MKV container. An unsupported plain data stream was removed in migration.	corpus
video/x-matroska	4	RFC, matroska.org	The file is migration from valid__h264_aac.mov using Migrate Apple ProRes file to FFV1 and FLAC streams in MKV container. An unsupported plain data stream was removed and audio stream checksum changed in migration.	corpus
video/x-matroska	4	RFC, matroska.org	The file is migration from valid__h264_aac_no_ftyp_atom.mov using Migrate Apple ProRes file to FFV1 and FLAC streams in MKV container. An unsupported plain data stream was removed in migration and audio stream checksum changed in migration.	corpus
video/x-matroska	4	RFC, matroska.org	The file is migration from valid__h265_aac.mov using Migrate Apple ProRes file to FFV1 and FLAC streams in MKV container. An unsupported plain data stream was removed and audio stream checksum changed in migration.	corpus

File repairs ¶

Recreate file with automatically selected audio and video streams ¶

The suggestion¶

Copy automatically selected audio and video streams and copy ‘global metadata’ to the new file.

Execution¶

ffmpeg -i <input file>.MOV -c:v copy -c:a copy -map_metadata 0 <output file>.MOV

Tested with: FFmpeg 6.0

Effects¶

The selected audio and video streams are copied along with top-level metadata (-map_metadata 0) to the output file.

The automatic selection principles are described in FFmpeg’s documentation: https://ffmpeg.org/ffmpeg.html#Automatic-stream-selection

Justification¶

The file contains single audio and video streams.

Migrated files¶

None found

Remake PDF with Acrobat Reader ¶

The suggestion¶

Open the file with Acrobat Reader and save it as a new file without any changes to the content.

Execution¶

Tested with:

Effects¶

Justification¶

Acrobat Reader is a standard implementation for PDF.

Migrated files¶

None found

Remake image with ImageMagick ¶

The suggestion¶

If the bits are not completely missing, use ImageMagick. If the bits are missing JHOVE reports ‘Expected marker byte 255 ‘ from JPEG-HUL and in that case 4 bytes can be added starting from position 7 in the file. Otherwise, the file more thoroughly corrupted.

Execution¶

convert <input file> <output file>

Tested with:

Effects¶

Justification¶

Migrated files¶

None found

View and save as new file ¶

The suggestion¶

Open the file in an image processing software and save it again in the same file format

Execution¶

Tested with:

Effects¶

Justification¶

Migrated files¶

None found

Recreate WAV file with single audio stream and metadata ¶

The suggestion¶

Copy the first audio stream and ‘global metadata’ of the stream 0 to a new file.

Execution¶

ffmpeg -i <input file>.WAV -vn -c:a copy -map_metadata 0 <output file>.WAV

Tested with: FFmpeg 6.0

Effects¶

Only the first audio stream in the file is copied from the input file to the output file. Video streams are explicitly excluded with -vn from the migration.

Justification¶

Only audio stream and metadata needs to be migrated.

Migrated files¶

None found

Remove annotations with Ghostscript ¶

The suggestion¶

Remove the annotations using Ghostscript. The process is called refrying (a PDF file).

Execution¶

gs -o <fixed file>.pdf -sDEVICE=pdfwrite -dPDFSETTINGS=/prepress -dPreserveAnnots=false <broken_file>.pdf

Tested with:

Effects¶

All annotations are removed. Ghostscript will convert the file from PDF to PostScript and back to PDF again. The file may lose other features in the process.

Read more about refrying here: https://www.prepressure.com/pdf/basics/refrying

Justification¶

The file will now be valid, however, you lose all annotations.

Migrated files¶

None found

Notice: any operation suggested on this page should be carefully considered before use, as this article is in continuous development.