Enable AMV encoding for audio

[shimmy]

The ​amv format is made for chinese s1mp3 hardware players, and is now part of the latest version of FFmpeg (0.9 - Harmony).

However, its underlying audio is adpcm_ima_amv, and this is unsupported by FFmpeg.

When I call ffmpeg -codecs, it contains the line D A D adpcm_ima_amv ADPCM IMA AMV, which means Decoding supported, Audio codec, Direct rendering, but it doesn't contain E which stands for Encoding.

I found the ​amv-codec-tools project, which supports this audio format automatically.

I think it would be easy to merge the outdated adpcm_ima_amv encoder from the amv-codec-tools into FFmpeg.

To be noted, compiling amv-codec-tools with the new FFmpeg version doesn't work, even I disable the amv and the adpcm_ima_amv encoders/decoders, I get this error:

[NULL @ 039a7860] Requested output format 'amv' is not a suitable output format
sample.amv: Invalid argument

Which is the same error that occurs when trying to use FFmpeg 0.9 for the AMV format - an issue that should be reported separately.

This issue is very urgent to me and I consider promoting a developer that will make it work.

[cehoyos]

​http://code.google.com/p/amv-codec-tools/source/list?path=/trunk/AMVmuxer/ffmpeg/libavcodec/adpcm.c

[shimmy]

Replying to cehoyos:

​http://code.google.com/p/amv-codec-tools/source/list?path=/trunk/AMVmuxer/ffmpeg/libavcodec/adpcm.c

The correct link to the file should be: ​adpcm.c

Here are links to the adpcm code-files in FFmpeg:
​adpcmenc.c​adpcm.c​adpcm.h​adpcm_data.c​adpcm_data.h

---

​More documentation on the AMV format
​Source code for an AMV decoder written in Perl

Anyone who has plans on implementing this any time soon, please contact me asap. This is very essential to me.
Thank a lot!

[zane]

Patchset pending review:
https://ffmpeg.org/pipermail/ffmpeg-devel/2020-November/271892.html

[zane]

Closed as of a2fea0f4690e4f11ba093f14509643c44a485165.