[vlc-commits] [Git][videolan/vlc][master] 4 commits: demux: mkv: do not call getChannelMask() with an empty mask
Steve Lhomme (@robUx4)
gitlab at videolan.org
Thu Aug 27 11:25:07 UTC 2026
Steve Lhomme pushed to branch master at VideoLAN / VLC
Commits:
ba76c8f1 by Steve Lhomme at 2026-08-27T11:13:59+00:00
demux: mkv: do not call getChannelMask() with an empty mask
It will return a match of 0 which is not valid.
- - - - -
cfb23590 by Steve Lhomme at 2026-08-27T11:13:59+00:00
demux: mkv: adjust indentation
No functional changes.
- - - - -
8bca8c90 by Steve Lhomme at 2026-08-27T11:13:59+00:00
demux: mkv: apply the default mask if not set
Similar to 277c4076cc5625efd50faaf0de0e8c36dc606276.
- - - - -
6061ca97 by Steve Lhomme at 2026-08-27T11:13:59+00:00
demux: mkv: verify the computed match is valid
Similar to what is done in wav.c we reset the channel mask if it's not.
- - - - -
1 changed file:
- modules/demux/mkv/matroska_segment_parse.cpp
Changes:
=====================================
modules/demux/mkv/matroska_segment_parse.cpp
=====================================
@@ -1978,46 +1978,76 @@ bool matroska_segment_c::TrackInit( mkv_track_t * p_tk )
if( p_tk->fmt.audio.i_channels > 2 &&
( p_tk->fmt.i_codec != VLC_CODEC_UNKNOWN ) )
{
+ unsigned i_channel_mask = 0;
uint32_t wfextcm = GetDWLE( p_tk->p_extra_data + offsetof(WAVEFORMATEXTENSIBLE, dwChannelMask) );
- int match;
- unsigned i_channel_mask = getChannelMask( &wfextcm,
- p_tk->fmt.audio.i_channels,
- &match );
-
- if( match < p_fmt->audio.i_channels )
+ if (wfextcm)
{
- int i_missing = p_fmt->audio.i_channels - match;
- msg_Warn( vars.p_demuxer, "Trying to fill up unspecified position for %d channels", p_fmt->audio.i_channels - match );
-
- static const uint32_t pi_pair[] = { AOUT_CHAN_REARLEFT|AOUT_CHAN_REARRIGHT,
- AOUT_CHAN_MIDDLELEFT|AOUT_CHAN_MIDDLERIGHT,
- AOUT_CHAN_LEFT|AOUT_CHAN_RIGHT };
+ int match;
+ i_channel_mask = getChannelMask( &wfextcm,
+ p_tk->fmt.audio.i_channels,
+ &match );
- /* Try to complete with pair */
- for( unsigned i = 0; i < ARRAY_SIZE(pi_pair); i++ )
+ if( match < p_fmt->audio.i_channels )
{
- if( i_missing >= 2 && !(i_channel_mask & pi_pair[i] ) )
+ int i_missing = p_fmt->audio.i_channels - match;
+ msg_Warn( vars.p_demuxer, "Trying to fill up unspecified position for %d channels", p_fmt->audio.i_channels - match );
+
+ static const uint32_t pi_pair[] = { AOUT_CHAN_REARLEFT|AOUT_CHAN_REARRIGHT,
+ AOUT_CHAN_MIDDLELEFT|AOUT_CHAN_MIDDLERIGHT,
+ AOUT_CHAN_LEFT|AOUT_CHAN_RIGHT };
+
+ /* Try to complete with pair */
+ for( unsigned i = 0; i < ARRAY_SIZE(pi_pair); i++ )
{
- i_missing -= 2;
- i_channel_mask |= pi_pair[i];
+ if( i_missing >= 2 && !(i_channel_mask & pi_pair[i] ) )
+ {
+ i_missing -= 2;
+ i_channel_mask |= pi_pair[i];
+ }
}
- }
- /* Well fill up with what we can */
- for( unsigned i = 0; i < ARRAY_SIZE(pi_channels_aout) && i_missing > 0; i++ )
- {
- if( !( i_channel_mask & pi_channels_aout[i] ) )
+ /* Well fill up with what we can */
+ for( unsigned i = 0; i < ARRAY_SIZE(pi_channels_aout) && i_missing > 0; i++ )
{
- i_channel_mask |= pi_channels_aout[i];
- i_missing--;
-
- if( i_missing <= 0 )
- break;
+ if( !( i_channel_mask & pi_channels_aout[i] ) )
+ {
+ i_channel_mask |= pi_channels_aout[i];
+ i_missing--;
+
+ if( i_missing <= 0 )
+ break;
+ }
}
+
+ match = p_fmt->audio.i_channels - i_missing;
+ }
+ if( match < p_fmt->audio.i_channels )
+ {
+ msg_Err( vars.p_demuxer, "Invalid/unsupported channel mask" );
+ i_channel_mask = 0;
}
+ }
- match = p_fmt->audio.i_channels - i_missing;
+ if( i_channel_mask == 0 && p_fmt->audio.i_channels <= AOUT_CHAN_MAX )
+ {
+ /* A dwChannelMask of 0 tells the audio device to render the first
+ * channel to the first port on the device, the second channel to the
+ * second port on the device, and so on. pi_default_channels is
+ * different than pi_channels_aout. Indeed FLC/FRC must be treated a
+ * SL/SR in that case. See "Default Channel Ordering" and "Details
+ * about dwChannelMask" from msdn */
+
+ static const uint32_t pi_default_channels[] = {
+ AOUT_CHAN_LEFT, AOUT_CHAN_RIGHT, AOUT_CHAN_CENTER,
+ AOUT_CHAN_LFE, AOUT_CHAN_REARLEFT, AOUT_CHAN_REARRIGHT,
+ AOUT_CHAN_MIDDLELEFT, AOUT_CHAN_MIDDLERIGHT, AOUT_CHAN_REARCENTER };
+
+ for( unsigned i = 0; i < p_fmt->audio.i_channels &&
+ i < ARRAY_SIZE(pi_default_channels);
+ i++ )
+ i_channel_mask |= pi_default_channels[i];
}
+
p_tk->fmt.i_codec = vlc_fourcc_GetCodecAudio( p_tk->fmt.i_codec,
p_tk->fmt.audio.i_bitspersample );
if( i_channel_mask )
View it on GitLab: https://code.videolan.org/videolan/vlc/-/compare/17dabd7ed47712c1beebd3b99c75d0b993e51ce6...6061ca97d97f3f14303c6ae99490f49525da0c7d
--
View it on GitLab: https://code.videolan.org/videolan/vlc/-/compare/17dabd7ed47712c1beebd3b99c75d0b993e51ce6...6061ca97d97f3f14303c6ae99490f49525da0c7d
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