diff options
Diffstat (limited to 'main/channel.c')
| -rw-r--r-- | main/channel.c | 26 |
1 files changed, 22 insertions, 4 deletions
diff --git a/main/channel.c b/main/channel.c index c50cb6e13..39130c35a 100644 --- a/main/channel.c +++ b/main/channel.c @@ -4127,8 +4127,25 @@ static void adjust_frame_for_plc(struct ast_channel *chan, struct ast_frame *fra int num_new_samples = frame->samples; struct plc_ds *plc = datastore->data; + /* As a general note, let me explain the somewhat odd calculations used when taking + * the frame offset into account here. According to documentation in frame.h, the frame's + * offset field indicates the number of bytes that the audio is offset. The plc->samples_buf + * is not an array of bytes, but rather an array of 16-bit integers since it holds SLIN + * samples. So I had two choices to make here with the offset. + * + * 1. Make the offset AST_FRIENDLY_OFFSET bytes. The main downside for this is that + * I can't just add AST_FRIENDLY_OFFSET to the plc->samples_buf and have the pointer + * arithmetic come out right. I would have to do some odd casting or division for this to + * work as I wanted. + * 2. Make the offset AST_FRIENDLY_OFFSET * 2 bytes. This allows the pointer arithmetic + * to work out better with the plc->samples_buf. The downside here is that the buffer's + * allocation contains an extra 64 bytes of unused space. + * + * I decided to go with option 2. This is why in the calloc statement and the statement that + * sets the frame's offset, AST_FRIENDLY_OFFSET is multiplied by 2. + */ - /* If this audio frame has no samples to fill in ignore it */ + /* If this audio frame has no samples to fill in, ignore it */ if (!num_new_samples) { return; } @@ -4139,7 +4156,7 @@ static void adjust_frame_for_plc(struct ast_channel *chan, struct ast_frame *fra */ if (plc->num_samples < num_new_samples) { ast_free(plc->samples_buf); - plc->samples_buf = ast_calloc(num_new_samples, sizeof(*plc->samples_buf)); + plc->samples_buf = ast_calloc(1, (num_new_samples * sizeof(*plc->samples_buf)) + (AST_FRIENDLY_OFFSET * 2)); if (!plc->samples_buf) { ast_channel_datastore_remove(chan, datastore); ast_datastore_free(datastore); @@ -4149,9 +4166,10 @@ static void adjust_frame_for_plc(struct ast_channel *chan, struct ast_frame *fra } if (frame->datalen == 0) { - plc_fillin(&plc->plc_state, plc->samples_buf, frame->samples); - frame->data.ptr = plc->samples_buf; + plc_fillin(&plc->plc_state, plc->samples_buf + AST_FRIENDLY_OFFSET, frame->samples); + frame->data.ptr = plc->samples_buf + AST_FRIENDLY_OFFSET; frame->datalen = num_new_samples * 2; + frame->offset = AST_FRIENDLY_OFFSET * 2; } else { plc_rx(&plc->plc_state, frame->data.ptr, frame->samples); } |