lavf: add a common function for selecting a pcm codec from parameters

libavformat/internal.h

@@ -358,4 +358,19 @@ unsigned int ff_codec_get_tag(const AVCodecTag *tags, enum AVCodecID id);
 
 enum AVCodecID ff_codec_get_id(const AVCodecTag *tags, unsigned int tag);
 
+/**
+ * Select a PCM codec based on the given parameters.
+ *
+ * @param bps     bits-per-sample
+ * @param flt     floating-point
+ * @param be      big-endian
+ * @param sflags  signed flags. each bit corresponds to one byte of bit depth.
+ *                e.g. the 1st bit indicates if 8-bit should be signed or
+ *                unsigned, the 2nd bit indicates if 16-bit should be signed or
+ *                unsigned, etc... This is useful for formats such as WAVE where
+ *                only 8-bit is unsigned and all other bit depths are signed.
+ * @return        a PCM codec id or AV_CODEC_ID_NONE
+ */
+enum AVCodecID ff_get_pcm_codec_id(int bps, int flt, int be, int sflags);
+
 #endif /* AVFORMAT_INTERNAL_H */

libavformat/mov.c

@@ -1057,33 +1057,12 @@ static int mov_read_stco(MOVContext *c, AVIOContext *pb, MOVAtom atom)
  */
 enum AVCodecID ff_mov_get_lpcm_codec_id(int bps, int flags)
 {
-    if (flags & 1) { // floating point
+    /* lpcm flags:
-        if (flags & 2) { // big endian
+     * 0x1 = float
-            if      (bps == 32) return AV_CODEC_ID_PCM_F32BE;
+     * 0x2 = big-endian
-            else if (bps == 64) return AV_CODEC_ID_PCM_F64BE;
+     * 0x4 = signed
-        } else {
+     */
-            if      (bps == 32) return AV_CODEC_ID_PCM_F32LE;
+    return ff_get_pcm_codec_id(bps, flags & 1, flags & 2, flags & 4 ? -1 : 0);
-            else if (bps == 64) return AV_CODEC_ID_PCM_F64LE;
-        }
-    } else {
-        if (flags & 2) {
-            if      (bps == 8)
-                // signed integer
-                if (flags & 4)  return AV_CODEC_ID_PCM_S8;
-                else            return AV_CODEC_ID_PCM_U8;
-            else if (bps == 16) return AV_CODEC_ID_PCM_S16BE;
-            else if (bps == 24) return AV_CODEC_ID_PCM_S24BE;
-            else if (bps == 32) return AV_CODEC_ID_PCM_S32BE;
-        } else {
-            if      (bps == 8)
-                if (flags & 4)  return AV_CODEC_ID_PCM_S8;
-                else            return AV_CODEC_ID_PCM_U8;
-            else if (bps == 16) return AV_CODEC_ID_PCM_S16LE;
-            else if (bps == 24) return AV_CODEC_ID_PCM_S24LE;
-            else if (bps == 32) return AV_CODEC_ID_PCM_S32LE;
-        }
-    }
-    return AV_CODEC_ID_NONE;
 }
 
 int ff_mov_read_stsd_entries(MOVContext *c, AVIOContext *pb, int entries)

libavformat/riff.c

@@ -678,15 +678,12 @@ enum AVCodecID ff_wav_codec_get_id(unsigned int tag, int bps)
     id = ff_codec_get_id(ff_codec_wav_tags, tag);
     if (id <= 0)
         return id;
-    /* handle specific u8 codec */
+
-    if (id == AV_CODEC_ID_PCM_S16LE && bps == 8)
+    if (id == AV_CODEC_ID_PCM_S16LE)
-        id = AV_CODEC_ID_PCM_U8;
+        id = ff_get_pcm_codec_id(bps, 0, 0, ~1);
-    if (id == AV_CODEC_ID_PCM_S16LE && bps == 24)
+    else if (id == AV_CODEC_ID_PCM_F32LE)
-        id = AV_CODEC_ID_PCM_S24LE;
+        id = ff_get_pcm_codec_id(bps, 1, 0, 0);
-    if (id == AV_CODEC_ID_PCM_S16LE && bps == 32)
+
-        id = AV_CODEC_ID_PCM_S32LE;
-    if (id == AV_CODEC_ID_PCM_F32LE && bps == 64)
-        id = AV_CODEC_ID_PCM_F64LE;
     if (id == AV_CODEC_ID_ADPCM_IMA_WAV && bps == 8)
         id = AV_CODEC_ID_PCM_ZORK;
     return id;

libavformat/utils.c

@@ -2135,6 +2135,36 @@ enum AVCodecID ff_codec_get_id(const AVCodecTag *tags, unsigned int tag)
     return AV_CODEC_ID_NONE;
 }
 
+enum AVCodecID ff_get_pcm_codec_id(int bps, int flt, int be, int sflags)
+{
+    if (flt) {
+        switch (bps) {
+        case 32: return be ? AV_CODEC_ID_PCM_F32BE : AV_CODEC_ID_PCM_F32LE;
+        case 64: return be ? AV_CODEC_ID_PCM_F64BE : AV_CODEC_ID_PCM_F64LE;
+        default: return AV_CODEC_ID_NONE;
+        }
+    } else {
+        bps >>= 3;
+        if (sflags & (1 << (bps - 1))) {
+            switch (bps) {
+            case 1:  return AV_CODEC_ID_PCM_S8;
+            case 2:  return be ? AV_CODEC_ID_PCM_S16BE : AV_CODEC_ID_PCM_S16LE;
+            case 3:  return be ? AV_CODEC_ID_PCM_S24BE : AV_CODEC_ID_PCM_S24LE;
+            case 4:  return be ? AV_CODEC_ID_PCM_S32BE : AV_CODEC_ID_PCM_S32LE;
+            default: return AV_CODEC_ID_NONE;
+            }
+        } else {
+            switch (bps) {
+            case 1:  return AV_CODEC_ID_PCM_U8;
+            case 2:  return be ? AV_CODEC_ID_PCM_U16BE : AV_CODEC_ID_PCM_U16LE;
+            case 3:  return be ? AV_CODEC_ID_PCM_U24BE : AV_CODEC_ID_PCM_U24LE;
+            case 4:  return be ? AV_CODEC_ID_PCM_U32BE : AV_CODEC_ID_PCM_U32LE;
+            default: return AV_CODEC_ID_NONE;
+            }
+        }
+    }
+}
+
 unsigned int av_codec_get_tag(const AVCodecTag * const *tags, enum AVCodecID id)
 {
     int i;