mirrors/gstreamer
mirrors/gstreamer
1
1
Fork 0
mirror of https://gitlab.freedesktop.org/gstreamer/gstreamer.git synced 2025-01-23 15:48:23 +00:00
Code Issues 1 Projects Releases Wiki Activity

flacparse: fix last frame timestamp in fixed block size mode

Browse source 
The last block may have a different block size, so we should not
use it to scale or we'll end up with a wrong timestamp.
See comment and quote from the FLAC format documentation in the code.

Fixes looped playback of FLAC files (via about-to-finish).

https://bugzilla.gnome.org/show_bug.cgi?id=661215
This commit is contained in:
Vincent Penquerc'h 2011-10-07 19:41:35 +01:00
parent 6a25727321
commit 14a9d1d66e
1 changed files with 28 additions and 2 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

30
gst/audioparsers/gstflacparse.c
View file

@ -532,6 +532,34 @@ gst_flac_parse_frame_header_is_valid (GstFlacParse * flacparse,
if (actual_crc != expected_crc)
goto error;
/*
The FLAC format documentation says:
The "blocking strategy" bit determines how to calculate the sample number
of the first sample in the frame. If the bit is 0 (fixed-blocksize), the
frame header encodes the frame number as above, and the frame's starting
sample number will be the frame number times the blocksize. If it is 1
(variable-blocksize), the frame header encodes the frame's starting
sample number itself. (In the case of a fixed-blocksize stream, only the
last block may be shorter than the stream blocksize; its starting sample
number will be calculated as the frame number times the previous frame's
blocksize, or zero if it is the first frame).
Therefore, when in fixed block size mode, we only update the block size
the first time, then reuse that block size for subsequent calls.
This will also fix a timestamp problem with the last block's timestamp
being miscalculated by scaling the block number by a "wrong" block size.
*/
if (blocking_strategy == 0) {
if (flacparse->block_size != 0) {
/* after first block */
if (flacparse->block_size != block_size) {
/* TODO: can we know we're on the last frame, to avoid warning ? */
GST_WARNING_OBJECT (flacparse, "Block size is not constant");
block_size = flacparse->block_size;
}
}
}
if (set) {
flacparse->block_size = block_size;
if (!flacparse->samplerate)
@ -692,7 +720,6 @@ gst_flac_parse_check_valid_frame (GstBaseParse * parse,
flacparse->offset = GST_BUFFER_OFFSET (buffer);
flacparse->blocking_strategy = 0;
flacparse->block_size = 0;
flacparse->sample_number = 0;
GST_DEBUG_OBJECT (flacparse, "Found sync code");
@ -1334,7 +1361,6 @@ gst_flac_parse_parse_frame (GstBaseParse * parse, GstBaseParseFrame * frame)
flacparse->offset = -1;
flacparse->blocking_strategy = 0;
flacparse->block_size = 0;
flacparse->sample_number = 0;
return GST_FLOW_OK;
}