ff_put_wav_header: add flag to force WAVEFORMATEX

Partially undoes commit 2c4e08d89327595f7f4be57dda4b3775e1198d5e:

    riff: always generate a proper WAVEFORMATEX structure in
    ff_put_wav_header

A new flag, FF_PUT_WAV_HEADER_FORCE_WAVEFORMATEX, is added to force the
use of WAVEFORMATEX rather than PCMWAVEFORMAT even for PCM codecs.

This flag is used in the Matroska muxer (the cause of the original
change) and in the ASF muxer, because the specifications for
these formats indicate explicitly that WAVEFORMATEX should be used.

Muxers for other formats will return to the original behavior of writing
PCMWAVEFORMAT when writing a header for raw PCM.

In particular, this causes raw PCM in WAV to generate the canonical
44-byte header expected by some tools.

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

1 files changed, 15 insertions, 1 deletions

diff --git a/libavformat/riff.h b/libavformat/riff.h
index dba38034e9..6f07179b2a 100644
--- a/libavformat/riff.h
+++ b/libavformat/riff.h
@@ -46,7 +46,21 @@ void ff_end_tag(AVIOContext *pb, int64_t start);
 int ff_get_bmp_header(AVIOContext *pb, AVStream *st, unsigned *esize);
 
 void ff_put_bmp_header(AVIOContext *pb, AVCodecContext *enc, const AVCodecTag *tags, int for_asf, int ignore_extradata);
-int ff_put_wav_header(AVIOContext *pb, AVCodecContext *enc);
+
+/**
+ * Tell ff_put_wav_header() to use WAVEFORMATEX even for PCM codecs.
+ */
+#define FF_PUT_WAV_HEADER_FORCE_WAVEFORMATEX    0x00000001
+
+/**
+ * Write WAVEFORMAT header structure.
+ *
+ * @param flags a combination of FF_PUT_WAV_HEADER_* constants
+ *
+ * @return the size or -1 on error
+ */
+int ff_put_wav_header(AVIOContext *pb, AVCodecContext *enc, int flags);
+
 enum AVCodecID ff_wav_codec_get_id(unsigned int tag, int bps);
 int ff_get_wav_header(AVIOContext *pb, AVCodecContext *codec, int size);