[Spice-devel] [PATCH spice-gtk] gst-audio: Do not update mmtime without real audio channel

[Christophe de Dinechin]

This looks better than my fix. Can’t ack right now (I did not build and test it yet), but that looks like a reasonable approach

> On 14 Jul 2017, at 14:24, Pavel Grunt <pgrunt at redhat.com> wrote:
> 
> This also fixes the huge memore leak reported by Christophe.
> Steps to reproduce:
> 1. ./configure --disable-pulse --enable-gstaudio
> 2. connect to a vm streaming video with no audio playing
> 3. see the memory grow really fast
> 
> It seems to be due to the fact that the "fake audio" channel updates the mmtime
> in a way that schedules the frames to the future ((unsigned) 0 - delay) and then
> gstreamer starts to queue the frames (they should be played later)
> 
> Pavel
> 
> On Fri, 2017-07-14 at 13:19 +0200, Pavel Grunt wrote:
>> The fake channel has been introduced to get the audio volume by starting
>> the gstreamer's audio pipeline and querring its volume info (see commit
>> aa8d044417bbf60685f59163b874ecb4f157c3c9).
>> 
>> Hovewer starting the pipeline updates the mmtime as a side effect. This
>> may cause a (big) delay in displaying a video stream.
>> 
>> Because the fake channel is only needed to get the volume info, make
>> sure to not update the mm-time with it.
>> 
>> Reported-by: Christophe de Dinechin <dinechin at redhat.com>
>> ---
>> src/spice-gstaudio.c | 11 +++++++----
>> 1 file changed, 7 insertions(+), 4 deletions(-)
>> 
>> diff --git a/src/spice-gstaudio.c b/src/spice-gstaudio.c
>> index 014c3a5..715f824 100644
>> --- a/src/spice-gstaudio.c
>> +++ b/src/spice-gstaudio.c
>> @@ -38,6 +38,7 @@ struct stream {
>>     GstElement              *sink;
>>     guint                   rate;
>>     guint                   channels;
>> +    gboolean                fake; /* fake channel just for getting info about
>> audio (volume) */
>> };
>> 
>> struct _SpiceGstaudioPrivate {
>> @@ -264,6 +265,8 @@ static gboolean update_mmtime_timeout_cb(gpointer data)
>>     SpiceGstaudioPrivate *p = gstaudio->priv;
>>     GstQuery *q;
>> 
>> +    g_return_val_if_fail(!p->playback.fake, TRUE);
>> +
>>     q = gst_query_new_latency();
>>     if (gst_element_query(p->playback.pipe, q)) {
>>         gboolean live;
>> @@ -326,7 +329,7 @@ cleanup:
>>     if (p->playback.pipe)
>>         gst_element_set_state(p->playback.pipe, GST_STATE_PLAYING);
>> 
>> -    if (p->mmtime_id == 0) {
>> +    if (!p->playback.fake && p->mmtime_id == 0) {
>>         update_mmtime_timeout_cb(gstaudio);
>>         p->mmtime_id = g_timeout_add_seconds(1, update_mmtime_timeout_cb,
>> gstaudio);
>>     }
>> @@ -569,7 +572,6 @@ static gboolean
>> spice_gstaudio_get_playback_volume_info_finish(SpiceAudio *audio
>>     GstElement *e;
>>     gboolean lmute;
>>     gdouble vol;
>> -    gboolean fake_channel = FALSE;
>>     GTask *task = G_TASK(res);
>> 
>>     g_return_val_if_fail(g_task_is_valid(task, audio), FALSE);
>> @@ -584,9 +586,9 @@ static gboolean
>> spice_gstaudio_get_playback_volume_info_finish(SpiceAudio *audio
>> 
>>     if (p->playback.sink == NULL || p->playback.channels == 0) {
>>         SPICE_DEBUG("PlaybackChannel not created yet, force start");
>> +        p->playback.fake = TRUE;
>>         /* In order to get system volume, we start the pipeline */
>>         playback_start(NULL, SPICE_AUDIO_FMT_S16, 2, 48000, audio);
>> -        fake_channel = TRUE;
>>     }
>> 
>>     if (GST_IS_BIN(p->playback.sink))
>> @@ -604,9 +606,10 @@ static gboolean
>> spice_gstaudio_get_playback_volume_info_finish(SpiceAudio *audio
>>     }
>>     g_object_unref(e);
>> 
>> -    if (fake_channel) {
>> +    if (p->playback.fake) {
>>         SPICE_DEBUG("Stop faked PlaybackChannel");
>>         playback_stop(SPICE_GSTAUDIO(audio));
>> +        p->playback.fake = FALSE;
>>     }
>> 
>>     if (mute != NULL) {