audio: remove S8, U16, U24, U32 formats

They are useless. Not only are they actually rarely in use; but
libavcodec doesn't even output them, as libavcodec has no such sample
formats for decoded audio.

Even if it should happen that we actually still need them (e.g. if doing
direct hardware output), there are better solutions. Swapping the sign
is a fast and lossless operation and can be done inplace, so AO actually
needing it could do this directly.

If you wonder why we keep U8 instead of S8: because libavcodec does it.

1 files changed, 7 insertions, 8 deletions

diff --git a/audio/format.c b/audio/format.c
index 401214281b..98957f9bd4 100644
--- a/audio/format.c
+++ b/audio/format.c
@@ -65,6 +65,12 @@ int af_fmt_change_bits(int format, int bits)
     return af_fmt_is_valid(format) ? format : 0;
 }
 
+// All formats are considered signed, except explicitly unsigned int formats.
+bool af_fmt_unsigned(int format)
+{
+    return format == AF_FORMAT_U8 || format == AF_FORMAT_U8P;
+}
+
 static const int planar_formats[][2] = {
     {AF_FORMAT_U8P,     AF_FORMAT_U8},
     {AF_FORMAT_S16P,    AF_FORMAT_S16},
@@ -101,12 +107,8 @@ int af_fmt_from_planar(int format)
 
 const struct af_fmt_entry af_fmtstr_table[] = {
     {"u8",          AF_FORMAT_U8},
-    {"s8",          AF_FORMAT_S8},
-    {"u16",         AF_FORMAT_U16},
     {"s16",         AF_FORMAT_S16},
-    {"u24",         AF_FORMAT_U24},
     {"s24",         AF_FORMAT_S24},
-    {"u32",         AF_FORMAT_U32},
     {"s32",         AF_FORMAT_S32},
     {"float",       AF_FORMAT_FLOAT},
     {"double",      AF_FORMAT_DOUBLE},
@@ -169,8 +171,7 @@ int af_str2fmt_short(bstr str)
 
 void af_fill_silence(void *dst, size_t bytes, int format)
 {
-    bool us = (format & AF_FORMAT_SIGN_MASK) == AF_FORMAT_US;
-    memset(dst, us ? 0x80 : 0, bytes);
+    memset(dst, af_fmt_unsigned(format) ? 0x80 : 0, bytes);
 }
 
 #define FMT_DIFF(type, a, b) (((a) & type) - ((b) & type))
@@ -191,8 +192,6 @@ int af_format_conversion_score(int dst_format, int src_format)
     int score = 1024;
     if (FMT_DIFF(AF_FORMAT_INTERLEAVING_MASK, dst_format, src_format))
         score -= 1;     // has to (de-)planarize
-    if (FMT_DIFF(AF_FORMAT_SIGN_MASK, dst_format, src_format))
-        score -= 4;     // has to swap sign
     if (FMT_DIFF(AF_FORMAT_TYPE_MASK, dst_format, src_format)) {
         int dst_bits = dst_format & AF_FORMAT_BITS_MASK;
         if ((dst_format & AF_FORMAT_TYPE_MASK) == AF_FORMAT_F) {