use ogg_page_granulepos to get number of samples written for Ogg FLAC (…

…#743)

Co-authored-by: Martijn van Beurden <[email protected]>

include/FLAC/stream_encoder.h

@@ -544,10 +544,11 @@ typedef FLAC__StreamEncoderReadStatus (*FLAC__StreamEncoderReadCallback)(const F
  * pair of calls several times in a batch with the same value of
  * \a current_frame.  When writing the page header, as well as in all but the
  * first page body write of the batch, the \a samples argument to the write
- * callback will be \c 0. The full number of samples of the batch will be
- * passed in the first page body write. Furthermore, it is possible that a few
- * of these samples are retained in an internal Ogg encoding buffer and not
- * actually encoded until the next batch.
+ * callback will be \c 0. For the write callback call containing the first
+ * page body, the \a samples argument is the number of samples contained in
+ * all newly added complete packets (not pages). This means that in case a
+ * packet is split over two pages, they are counted in the samples argument
+ * of the page on which the packet is completed.
  *
  * \note In general, FLAC__StreamEncoder functions which change the
  * state should not be called on the \a encoder while in the callback.

src/libFLAC/include/private/ogg_encoder_aspect.h

@@ -49,7 +49,7 @@ typedef struct FLAC__OggEncoderAspect {
 	FLAC__bool seen_magic; /* true if we've seen the fLaC magic in the write callback yet */
 	FLAC__bool is_first_packet;
 	FLAC__uint64 samples_written;
-	uint32_t samples_in_submit_buffer;
+	FLAC__int64 last_page_granule_pos;
 } FLAC__OggEncoderAspect;
 
 void FLAC__ogg_encoder_aspect_set_serial_number(FLAC__OggEncoderAspect *aspect, long value);

src/libFLAC/ogg_encoder_aspect.c

@@ -57,7 +57,7 @@ FLAC__bool FLAC__ogg_encoder_aspect_init(FLAC__OggEncoderAspect *aspect)
 	aspect->seen_magic = false;
 	aspect->is_first_packet = true;
 	aspect->samples_written = 0;
-	aspect->samples_in_submit_buffer = 0;
+	aspect->last_page_granule_pos = 0;
 
 	return true;
 }
@@ -197,23 +197,40 @@ FLAC__StreamEncoderWriteStatus FLAC__ogg_encoder_aspect_write_callback_wrapper(F
 		 * first non-metadata page body call, and then set to zero in case there are more iterations of the while loop (so
 		 * as not to give the impression of more samples being processed).
 		 */
-		aspect->samples_in_submit_buffer += samples;
 		if(is_metadata) {
 			while(ogg_stream_flush(&aspect->stream_state, &aspect->page) != 0) {
+				FLAC__int64 page_granule_pos = ogg_page_granulepos(&aspect->page);
+				uint32_t samples_on_this_page;
+				if(page_granule_pos == -1) {
+					/* a granule position of -1 means no packets finish on this page */
+					samples_on_this_page = 0;
+				}
+				else {
+					samples_on_this_page = (uint32_t)(page_granule_pos - aspect->last_page_granule_pos);
+					aspect->last_page_granule_pos = page_granule_pos;
+				}
 				if(write_callback(encoder, aspect->page.header, aspect->page.header_len, 0, current_frame, client_data) != FLAC__STREAM_ENCODER_WRITE_STATUS_OK)
 					return FLAC__STREAM_ENCODER_WRITE_STATUS_FATAL_ERROR;
-				if(write_callback(encoder, aspect->page.body, aspect->page.body_len, aspect->samples_in_submit_buffer, current_frame, client_data) != FLAC__STREAM_ENCODER_WRITE_STATUS_OK)
+				if(write_callback(encoder, aspect->page.body, aspect->page.body_len, samples_on_this_page, current_frame, client_data) != FLAC__STREAM_ENCODER_WRITE_STATUS_OK)
 					return FLAC__STREAM_ENCODER_WRITE_STATUS_FATAL_ERROR;
-				aspect->samples_in_submit_buffer = 0;
 			}
 		}
 		else {
 			while(ogg_stream_pageout(&aspect->stream_state, &aspect->page) != 0) {
+				FLAC__int64 page_granule_pos = ogg_page_granulepos(&aspect->page);
+				uint32_t samples_on_this_page;
+				if(page_granule_pos == -1) {
+					/* a granule position of -1 means no packets finish on this page */
+					samples_on_this_page = 0;
+				}
+				else {
+					samples_on_this_page = (uint32_t)(page_granule_pos - aspect->last_page_granule_pos);
+					aspect->last_page_granule_pos = page_granule_pos;
+				}
 				if(write_callback(encoder, aspect->page.header, aspect->page.header_len, 0, current_frame, client_data) != FLAC__STREAM_ENCODER_WRITE_STATUS_OK)
 					return FLAC__STREAM_ENCODER_WRITE_STATUS_FATAL_ERROR;
-				if(write_callback(encoder, aspect->page.body, aspect->page.body_len, aspect->samples_in_submit_buffer, current_frame, client_data) != FLAC__STREAM_ENCODER_WRITE_STATUS_OK)
+				if(write_callback(encoder, aspect->page.body, aspect->page.body_len, samples_on_this_page, current_frame, client_data) != FLAC__STREAM_ENCODER_WRITE_STATUS_OK)
 					return FLAC__STREAM_ENCODER_WRITE_STATUS_FATAL_ERROR;
-				aspect->samples_in_submit_buffer = 0;
 			}
 		}
 	}