[Libav-user] MXF muxer generates incomplete file

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[Libav-user] MXF muxer generates incomplete file

Alan Moore
All,

I'm using libavformat to generate an mxf file and for the most part it seems to be working but some files seem to be unable to import/link into Avid Media Composer. I've inspected the structure of the file and have seen two different conditions that appear to be triggering the failed import/link.

1) Last frame of video has all the audio channel essences but those essences are smaller than all the rest.

2) Last frame of video is missing some of the audio channel essences (but they are the same size as all the rest.)

It seems to happen in various frame rates/formats and only happens occassionally (timing?) As far as I know I'm writing out all the audio channel data for each frame. I am buffering the audio in my app (one second's worth)  and writing the audio out when the cache is full (48K AES audio) and so each call to av_interleaved_write_frame is given 72k (two channels.)

For problem #1 I have written a special case to flush out a full second's worth of audio even if I have to pad it with silence but this just seems to force problem #2 and generates a problematic file every time.

Has anyone run across any issues with end-of-file audio issues with ffmpeg and mxf files?

FYI: I am not using ffmpeg's codec(s) as I have a hardware DNX encoder so I'm just using libavformat.

Thanks in advance!

Alan

--
"Whatever you can do, or dream you can do, begin it. Boldness has genius, power, and magic in it. Begin it now." - Goethe

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Re: MXF muxer generates incomplete file

Carl Eugen Hoyos-2
2017-03-28 22:09 GMT+02:00 Alan Moore <[hidden email]>:

> I'm using libavformat to generate an mxf file and for the most part it seems
> to be working but some files seem to be unable to import/link into Avid
> Media Composer.

Is this reproducible with ffmpeg (the application)?

Carl Eugen
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Re: MXF muxer generates incomplete file

Alan Moore
Thanks for responding so quickly.

I haven't tried but I'm guessing not mainly because we don't use anything other than libavformat. I'll give it a try just in case.

Thanks!

Alan

> On Mar 28, 2017, at 3:00 PM, Carl Eugen Hoyos <[hidden email]> wrote:
>
> 2017-03-28 22:09 GMT+02:00 Alan Moore <[hidden email]>:
>
>> I'm using libavformat to generate an mxf file and for the most part it seems
>> to be working but some files seem to be unable to import/link into Avid
>> Media Composer.
>
> Is this reproducible with ffmpeg (the application)?
>
> Carl Eugen
> _______________________________________________
> Libav-user mailing list
> [hidden email]
> http://ffmpeg.org/mailman/listinfo/libav-user
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