| Message ID | 20200812222658.29282-1-jeebjp@gmail.com |
|---|---|
| State | Accepted |
| Commit | 1c7e55dd504245d71444fac1a73e5370cc76fede |
| Headers | show |
| Series | [FFmpeg-devel] swresample/rematrix: handle 22.2 as a 9 channel layout | expand |
| Context | Check | Description |
|---|---|---|
| andriy/default | pending | |
| andriy/make | success | Make finished |
| andriy/make_fate | success | Make fate finished |
On Thu, Aug 13, 2020 at 01:26:58AM +0300, Jan Ekström wrote: > This is as far as 22.2 follows the same channel order as > WaveFormatExtensible's channel mask (and the AV_CH_* defines). > > After LFE2 the side channels would follow, but that offset of > one stops us from utilizing them without further tweaks. > > This change was verified by using swresample to downmix to 5.1, > and then feeding that to WASAPI. > --- > libswresample/rematrix.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) probably ok [...]
On Fri, Aug 14, 2020 at 8:36 PM Michael Niedermayer <michael@niedermayer.cc> wrote: > > On Thu, Aug 13, 2020 at 01:26:58AM +0300, Jan Ekström wrote: > > This is as far as 22.2 follows the same channel order as > > WaveFormatExtensible's channel mask (and the AV_CH_* defines). > > > > After LFE2 the side channels would follow, but that offset of > > one stops us from utilizing them without further tweaks. > > > > This change was verified by using swresample to downmix to 5.1, > > and then feeding that to WASAPI. > > --- > > libswresample/rematrix.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > probably ok > Thanks for taking a look. I originally planned on sending a link to a test sample I created somewhere during the time attempting to validate the AAC decoder, which I then also utilized to check the result of this: https://megumin.fushizen.eu/samples/22.2_input_test_sample.wav ...but alas then I never got to it afterwards. Jan
On Sat, Aug 15, 2020 at 12:29 PM Jan Ekström <jeebjp@gmail.com> wrote: > > On Fri, Aug 14, 2020 at 8:36 PM Michael Niedermayer > <michael@niedermayer.cc> wrote: > > > > On Thu, Aug 13, 2020 at 01:26:58AM +0300, Jan Ekström wrote: > > > This is as far as 22.2 follows the same channel order as > > > WaveFormatExtensible's channel mask (and the AV_CH_* defines). > > > > > > After LFE2 the side channels would follow, but that offset of > > > one stops us from utilizing them without further tweaks. > > > > > > This change was verified by using swresample to downmix to 5.1, > > > and then feeding that to WASAPI. > > > --- > > > libswresample/rematrix.c | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > probably ok > > > > Thanks for taking a look. I originally planned on sending a link to a > test sample I created somewhere during the time attempting to validate > the AAC decoder, which I then also utilized to check the result of > this: > https://megumin.fushizen.eu/samples/22.2_input_test_sample.wav > > ...but alas then I never got to it afterwards. > Aand once again hit the send button a bit too soon. For context, the reason why I started poking at this a bit more is because a friendly person elsewhere who implemented 22.2 to X downmix on his side pointed out that https://www.itu.int/dms_pub/itu-r/opb/rep/R-REP-BS.2159-8-2019-PDF-E.pdf contained the downmix matrix to 5.1 (TABLE11, System H is 22.2). So I planned on taking the same shortcut of doing 22.2->5.1->X, since 5.1 was already implemented or could be pushed to most audio output systems, but after looking at rematrix for a bit I got that no such shortcuts would be possible. So now the plan is to attempt to see if: 1) I can work around the +1 offset for side left/right, thus creating the base level 10.1 that seems to be implemented in rematrix. 2) Mix top/bottom channels into their matching base level, adding support for them being mixed in. 3) Mix LFE2 into LFE1. If this would work, we could get a downmix going by means of 22.2->10.1->X . Jan
On Fri, Aug 14, 2020 at 8:36 PM Michael Niedermayer <michael@niedermayer.cc> wrote: > > On Thu, Aug 13, 2020 at 01:26:58AM +0300, Jan Ekström wrote: > > This is as far as 22.2 follows the same channel order as > > WaveFormatExtensible's channel mask (and the AV_CH_* defines). > > > > After LFE2 the side channels would follow, but that offset of > > one stops us from utilizing them without further tweaks. > > > > This change was verified by using swresample to downmix to 5.1, > > and then feeding that to WASAPI. > > --- > > libswresample/rematrix.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > probably ok > Applied as 1c7e55dd504245d71444fac1a73e5370cc76fede . Jan
diff --git a/libswresample/rematrix.c b/libswresample/rematrix.c index d0c4a212b3..94b3de88f6 100644 --- a/libswresample/rematrix.c +++ b/libswresample/rematrix.c @@ -143,7 +143,7 @@ av_cold int swr_build_matrix(uint64_t in_ch_layout_param, uint64_t out_ch_layout if (in_ch_layout == AV_CH_LAYOUT_22POINT2 && out_ch_layout != AV_CH_LAYOUT_22POINT2) { - in_ch_layout = AV_CH_LAYOUT_5POINT1_BACK; + in_ch_layout = (AV_CH_LAYOUT_7POINT1_WIDE_BACK|AV_CH_BACK_CENTER); av_get_channel_layout_string(buf, sizeof(buf), -1, in_ch_layout); av_log(log_context, AV_LOG_WARNING, "Full-on remixing from 22.2 has not yet been implemented! "