This involved a review of the Firefox parsing code along
with the official specifcation, and setting these fields
to the specified default values.
Most notably, I have found that recent browsers do not need the
8 ms pre skip, and it seems to remove some audio lag to
switch to 0.
Signed-off-by: Jeremy White <jwhite@xxxxxxxxxxxxxxx>
---
webm.js | 27 +++++++++++++++++++--------
1 file changed, 19 insertions(+), 8 deletions(-)
diff --git a/webm.js b/webm.js
index 789da14..72c1853 100644
--- a/webm.js
+++ b/webm.js
@@ -393,28 +393,39 @@ webm_SeekHead.prototype =
function webm_AudioTrackEntry()
{
+ /*
+ ** In general, we follow this specification:
+ ** https://www.matroska.org/technical/specs/index.html
+ ** we supply the mandatory values, and a comment notes
+ ** where we differ from the default
+ ** There is one RECOMMENDED guideline we are omitting;
+ ** the OPUS codec_delay is recommended to be 80ms.
+ ** However, the spice server does not currently provide time
+ ** stamps that are offset by 80ms, so you effectively get an
+ ** 80ms lag with this setting.
+ */
this.id = WEBM_TRACK_ENTRY;
this.number = 1;
this.uid = 1;
this.type = 2; // Audio
this.flag_enabled = 1;
this.flag_default = 1;
- this.flag_forced = 1;
- this.flag_lacing = 0;
- this.min_cache = 0; // fixme - check
+ this.flag_forced = 1; // Different than default; we wish to force
+ this.flag_lacing = 1;
+ this.min_cache = 0;
this.max_block_addition_id = 0;
- this.codec_decode_all = 0; // fixme - check
- this.seek_pre_roll = 0; // 80000000; // fixme - check
- this.codec_delay = 80000000; // Must match codec_private.preskip
+ this.seek_pre_roll = 0;
+ this.codec_delay = 0; // Must match codec_private.preskip
this.codec_id = "A_OPUS";
+ this.codec_decode_all = 1;
this.audio = new webm_Audio(OPUS_FREQUENCY);
// See: http://tools.ietf.org/html/draft-terriberry-oggopus-01
this.codec_private = [ 0x4f, 0x70, 0x75, 0x73, 0x48, 0x65, 0x61, 0x64, // OpusHead
0x01, // Version
OPUS_CHANNELS,
- 0x00, 0x0F, // Preskip - 3840 samples - should be 8ms at 48kHz
- 0x80, 0xbb, 0x00, 0x00, // 48000
+ 0x00, 0x00, // Preskip - 3840 samples would be 8ms at 48kHz
+ 0x80, 0xbb, 0x00, 0x00, // nominal rate - 48000
0x00, 0x00, // Output gain
0x00 // Channel mapping family
];
--
2.1.4
_______________________________________________
Spice-devel mailing list
Spice-devel@xxxxxxxxxxxxxxxxxxxxx
https://lists.freedesktop.org/mailman/listinfo/spice-devel