Hi Jason

On Sat, Dec 20, 2025 at 10:28:39PM +0100, Jason A. Donenfeld via ffmpeg-devel wrote:
> Currently if you encode a large wav, ffmpeg will hint after the fact
> that the resultant file is corrupted, because traditional wav cannot
> handle lengths greater than 32-bits. This isn't very useful; nobody
> benefits from getting garbage files.
> 
> You can manually work around this by adding `-rf64 always`, which most
> players have support for. Most people don't remember to do this until
> after the fact when their file is corrupted, or they don't figure it out
> at all and wind up using the w64 container instead.
> 
> And so that's what `-rf64 auto` is for. It uses the larger format when
> needed, and if not, uses the traditional wav that is probably more
> compatible. The result of using `-rf64 auto` is that you can add it to
> every command line -- and should add it to every command line -- to get
> either a normal small file, or a non-corrupt large file.
> 
> This is a very sensible default to have on, rather than just producing
> corrupt files and having users scrambling for solutions, and then having
> to do a potentially expensive reencode after. With `-rf64 auto` on by
> default, the user always gets a readable good file. And for users who
> sometimes want corrupt files, there still exists `-rf64 never` that can
> be enabled.
> ---
>  libavformat/wavenc.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/libavformat/wavenc.c b/libavformat/wavenc.c
> index a515f4e2a2..835a2157bc 100644
> --- a/libavformat/wavenc.c
> +++ b/libavformat/wavenc.c
> @@ -487,7 +487,7 @@ static const AVOption options[] = {
>      { "off",        "Do not write peak chunk.",              0,                  AV_OPT_TYPE_CONST, { .i64 = PEAK_OFF  }, 0, 0, ENC, .unit = "peak" },
>      { "on",         "Append peak chunk after wav data.",     0,                  AV_OPT_TYPE_CONST, { .i64 = PEAK_ON   }, 0, 0, ENC, .unit = "peak" },
>      { "only",       "Write only peak chunk, omit wav data.", 0,                  AV_OPT_TYPE_CONST, { .i64 = PEAK_ONLY }, 0, 0, ENC, .unit = "peak" },
> -    { "rf64",       "Use RF64 header rather than RIFF for large files.",    OFFSET(rf64), AV_OPT_TYPE_INT,   { .i64 = RF64_NEVER  },-1, 1, ENC, .unit = "rf64" },
> +    { "rf64",       "Use RF64 header rather than RIFF for large files.",    OFFSET(rf64), AV_OPT_TYPE_INT,   { .i64 = RF64_AUTO  },-1, 1, ENC, .unit = "rf64" },
>      { "auto",       "Write RF64 header if file grows large enough.",        0,            AV_OPT_TYPE_CONST, { .i64 = RF64_AUTO   }, 0, 0, ENC, .unit = "rf64" },
>      { "always",     "Always write RF64 header regardless of file size.",    0,            AV_OPT_TYPE_CONST, { .i64 = RF64_ALWAYS }, 0, 0, ENC, .unit = "rf64" },
>      { "never",      "Never write RF64 header regardless of file size.",     0,            AV_OPT_TYPE_CONST, { .i64 = RF64_NEVER  }, 0, 0, ENC, .unit = "rf64" },

breaks fate:

--- -	2025-12-21 04:04:18.901071242 +0100
+++ tests/data/fate/filter-channelmap-one-str	2025-12-21 04:04:18.898363748 +0100
@@ -1 +1 @@
-e18791f65ce5861e130b2c3e472ab90a
+8f8a664b694f18e1e9ae1b9ccfa6f30c
Test filter-channelmap-one-str failed. Look at tests/data/fate/filter-channelmap-one-str.err for details.
make: *** [tests/Makefile:323: fate-filter-channelmap-one-str] Error 1

if this change is intended, then update the fate tests and explain in the commit message
why they change

thx

[...]

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