format_pcm: Correct behavior of fseek and ftell for G.722
authorSean Bright <sean.bright@gmail.com>
Wed, 18 Apr 2018 18:40:49 +0000 (14:40 -0400)
committerSean Bright <sean.bright@gmail.com>
Wed, 18 Apr 2018 18:43:01 +0000 (12:43 -0600)
There are twice as many samples in the same number of bytes, so redefine
some of the G.722 format functions in terms of their PCM counterparts.

Change-Id: I6a8c7352624b930a5f2d9e4857f75283fa5dd9f9

formats/format_pcm.c

index 35612c9..4e846d7 100644 (file)
@@ -91,10 +91,7 @@ static struct ast_frame *pcm_read(struct ast_filestream *s, int *whennext)
                return NULL;
        }
        s->fr.datalen = res;
-       if (ast_format_cmp(s->fmt->format, ast_format_g722) == AST_FORMAT_CMP_EQUAL)
-               *whennext = s->fr.samples = res * 2;
-       else
-               *whennext = s->fr.samples = res;
+       *whennext = s->fr.samples = res;
        return &s->fr;
 }
 
@@ -410,16 +407,11 @@ static int au_rewrite(struct ast_filestream *s, const char *comment)
 static int au_seek(struct ast_filestream *fs, off_t sample_offset, int whence)
 {
        off_t min, max, cur;
-       long offset = 0, bytes;
+       long offset = 0;
        struct au_desc *desc = fs->_private;
 
        min = desc->hdr_size;
 
-       if (ast_format_cmp(fs->fmt->format, ast_format_g722) == AST_FORMAT_CMP_EQUAL)
-               bytes = sample_offset / 2;
-       else
-               bytes = sample_offset;
-
        if ((cur = ftello(fs->f)) < 0) {
                ast_log(AST_LOG_WARNING, "Unable to determine current position in au filestream %p: %s\n", fs, strerror(errno));
                return -1;
@@ -436,11 +428,11 @@ static int au_seek(struct ast_filestream *fs, off_t sample_offset, int whence)
        }
 
        if (whence == SEEK_SET)
-               offset = bytes + min;
+               offset = sample_offset + min;
        else if (whence == SEEK_CUR || whence == SEEK_FORCECUR)
-               offset = bytes + cur;
+               offset = sample_offset + cur;
        else if (whence == SEEK_END)
-               offset = max - bytes;
+               offset = max - sample_offset;
 
        if (whence != SEEK_FORCECUR) {
                offset = (offset > max) ? max : offset;
@@ -479,6 +471,23 @@ static off_t au_tell(struct ast_filestream *fs)
        return offset - desc->hdr_size;
 }
 
+static struct ast_frame *g722_read(struct ast_filestream *s, int *whennext)
+{
+       struct ast_frame *f = pcm_read(s, whennext);
+       *whennext = s->fr.samples = (*whennext * 2);
+       return f;
+}
+
+static int g722_seek(struct ast_filestream *fs, off_t sample_offset, int whence)
+{
+       return pcm_seek(fs, sample_offset / 2, whence);
+}
+
+static off_t g722_tell(struct ast_filestream *fs)
+{
+       return pcm_tell(fs) * 2;
+}
+
 static struct ast_format_def alaw_f = {
        .name = "alaw",
        .exts = "alaw|al|alw",
@@ -510,10 +519,10 @@ static struct ast_format_def g722_f = {
        .name = "g722",
        .exts = "g722",
        .write = pcm_write,
-       .seek = pcm_seek,
+       .seek = g722_seek,
        .trunc = pcm_trunc,
-       .tell = pcm_tell,
-       .read = pcm_read,
+       .tell = g722_tell,
+       .read = g722_read,
        .buf_size = (BUF_SIZE * 2) + AST_FRIENDLY_OFFSET,
 };