-solved- different file-size after c:a copy - why?

[ThomasM]

Hi there,

I´m experimenting with ffAStrans. Nice tool, very good work.

I did a workflow which is part of another workflow. It is checking the (audio-)files, if they have a correct extension (.wav). I tried to upload the workflow-xml, but it does not work. So here is my description:

1. node: Watchfolder; deny System and Hidden; Recurse access.
2. node: operation Conditional; If %s_original_ext% <> ??? then [next node]
3. node: Decoder A/V-Media; use Audio
4. node: Channel Mapper; Stereo 1->1 2->2
5. node: Custom ffmpeg: Audio codec DISABLED; Video-Codec DISABLED; Options: -c:a copy; Extension: .wav
6. node: Deliverys: Folder; C:\Tom\mit_Endung\%s_original_path~2%\%s_original_path~1%; no check-boxes selected.

When I start the workflow everything works, but... the file-size of the destination-file is larger than the input-file ( input: 71.707 KB; output: 78.044 KB)

The Input and output-folders are on the same machine, ffastrans runs on the same machine. Version is FFasTRANS0.7.7 on Win 7 pro.

Any ideas?

Thank you in advance,

tom

[ThomasM]

once again me.

I figured out that the resulting file is 48KHz instead of the original 44.1KHz. I did not expect this because of the "copy" command in the custom FFmpeg node (Node number 5 in my last post).

I also tried:
5. node: Custom ffmpeg: Audio codec DISABLED; Video-Codec DISABLED; Options: -c:a copy -ar 44100; Extension: .wav

where -ar 44100 is new to the options. But the result is the same. What do I do wrong?

regards,

tom

[admin]

Hi Thomas,

When you're using the "A/V Media"-decoder it will conform all audio to 16bit 48kHz. So when you're specifying "-c:a copy" in your command you're actually telling ffmpeg to stream copy the audio from the decoder untouched (via channel mapper). So because stream copying omits all parameters related to encoding of the stream you must specify "pcm_s16le" as your audio codec: "-c:a pcm_s16le -ar 44100".

Hope this helps

-steinar

[ThomasM]

Steinar,

thank you so much, I did not know that. I just killed node 3 and node 4, now it works.

Success!