Add an example program that streams audio using ffmpeg

1 files changed, 66 insertions, 0 deletions

diff --git a/examples/alffmpeg.h b/examples/alffmpeg.h
new file mode 100644
index 00000000..7fa88e65
--- /dev/null
+++ b/examples/alffmpeg.h
@@ -0,0 +1,66 @@
+#ifndef ALFFMPEG_H
+#define ALFFMPEG_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif /* __cplusplus */
+
+#include <libavcodec/avcodec.h>
+#include <libavformat/avformat.h>
+
+/* Opaque handles to files and streams. Apps don't need to concern themselves
+ * with the internals */
+typedef struct MyFile *FilePtr;
+typedef struct MyStream *StreamPtr;
+
+/* Opens a file with ffmpeg and sets up the streams' information */
+FilePtr openAVFile(const char *fname);
+
+/* Opens a named file image with ffmpeg and sets up the streams' information */
+FilePtr openAVData(const char *name, char *buffer, size_t buffer_len);
+
+/* Opens a named data stream with ffmpeg, using the specified data pointer and
+ * callbacks, and sets up the streams' information */
+FilePtr openAVCustom(const char *name, void *user_data,
+                     int (*read_packet)(void *user_data, uint8_t *buf, int buf_size),
+                     int (*write_packet)(void *user_data, uint8_t *buf, int buf_size),
+                     int64_t (*seek)(void *user_data, int64_t offset, int whence));
+
+/* Closes/frees an opened file and any of its streams */
+void closeAVFile(FilePtr file);
+
+/* Reports certain information from the file, eg, the number of audio
+ * streams. Returns 0 on success. */
+int getAVFileInfo(FilePtr file, int *numaudiostreams);
+
+/* Retrieves a handle for the given audio stream number (generally 0, but some
+ * files can have multiple audio streams in one file). */
+StreamPtr getAVAudioStream(FilePtr file, int streamnum);
+
+/* Returns information about the given audio stream. Returns 0 on success. */
+int getAVAudioInfo(StreamPtr stream, ALuint *rate, ALenum *channels, ALenum *type);
+
+/* Returns a pointer to the next available packet of decoded audio. Any data
+ * from a previously-decoded packet is dropped. The size (in bytes) of the
+ * returned data buffer is stored in 'length', and the returned pointer is only
+ * valid until the next call to getAVAudioData or readAVAudioData. */
+void *getAVAudioData(StreamPtr stream, size_t *length);
+
+/* The "meat" function. Decodes audio and writes, at most, length bytes into
+ * the provided data buffer. Will only return less for end-of-stream or error
+ * conditions. Returns the number of bytes written. */
+size_t readAVAudioData(StreamPtr stream, void *data, size_t length);
+
+/* Decodes all remaining data from the stream and returns a buffer containing
+ * the audio data, with the size stored in 'length'. The returned pointer must
+ * be freed with a call to free(). Note that since this decodes the whole
+ * stream, using it on lengthy streams (eg, music) will use a lot of memory.
+ * Such streams are better handled using getAVAudioData or readAVAudioData to
+ * keep smaller chunks in memory at any given time. */
+void *decodeAVAudioStream(StreamPtr stream, size_t *length);
+
+#ifdef __cplusplus
+}
+#endif /* __cplusplus */
+
+#endif /* ALFFMPEG_H */