[vlc-devel] [PATCH 4/5] wasapi: add 24bits support

[Rémi Denis-Courmont]

So what? Some cards don't support PCM at all, or only some really weird formats. That's why we use the OS-provided HAL.

I don't think this belongs in VLC. We already decided to drop 24-bits PCM earlier.

Le 24 octobre 2019 15:37:12 GMT+03:00, Thomas Guillem <thomas at gllm.fr> a écrit :
>But don't use VLC_CODEC_S24N as this fourcc is not handled by any audio
>filters. Instead, request VLC_CODEC_S32N to VLC and do the conversion
>internally.
>
>This commit is needed by the next commit since some sound cards only
>support
>24bits.
>---
> modules/audio_output/wasapi.c | 30 +++++++++++++++++++++++++++---
> 1 file changed, 27 insertions(+), 3 deletions(-)
>
>diff --git a/modules/audio_output/wasapi.c
>b/modules/audio_output/wasapi.c
>index d6105169b8e..daa946f8afc 100644
>--- a/modules/audio_output/wasapi.c
>+++ b/modules/audio_output/wasapi.c
>@@ -106,6 +106,7 @@ typedef struct aout_stream_sys
>     unsigned block_align;
>     UINT64 written; /**< Frames written to the buffer */
>     UINT32 frames; /**< Total buffer size (frames) */
>+    bool s24s32; /**< Output configured as S24N, but input as S32N */
> } aout_stream_sys_t;
> 
> static void ResetTimer(aout_stream_t *s)
>@@ -268,7 +269,28 @@ static HRESULT Play(aout_stream_t *s, block_t
>*block, vlc_tick_t date)
> 
>         const size_t copy = frames * sys->block_align;
> 
>-        memcpy(dst, block->p_buffer, copy);
>+        if (!sys->s24s32)
>+        {
>+            memcpy(dst, block->p_buffer, copy);
>+            block->p_buffer += copy;
>+            block->i_buffer -= copy;
>+        }
>+        else
>+        {
>+            /* Convert back S32L to S24L. The following is doing the
>opposite
>+             * of S24LDecode() from codec/araw.c */
>+            BYTE *end = dst + copy;
>+            while (dst < end)
>+            {
>+                dst[0] = block->p_buffer[1];
>+                dst[1] = block->p_buffer[2];
>+                dst[2] = block->p_buffer[3];
>+                dst += 3;
>+                block->p_buffer += 4;
>+                block->i_buffer -= 4;
>+            }
>+
>+        }
>         hr = IAudioRenderClient_ReleaseBuffer(render, frames, 0);
>         if (FAILED(hr))
>         {
>@@ -276,8 +298,6 @@ static HRESULT Play(aout_stream_t *s, block_t
>*block, vlc_tick_t date)
>             break;
>         }
> 
>-        block->p_buffer += copy;
>-        block->i_buffer -= copy;
>         block->i_nb_samples -= frames;
>         sys->written += frames;
>         if (block->i_nb_samples == 0)
>@@ -512,6 +532,7 @@ static int vlc_FromWave(const WAVEFORMATEX
>*restrict wf,
>             switch (wf->wBitsPerSample)
>             {
>                 case 32:
>+                case 24:
>                     audio->i_format = VLC_CODEC_S32N;
>                     break;
>                 case 16:
>@@ -679,6 +700,9 @@ static HRESULT Start(aout_stream_t *s,
>audio_sample_format_t *restrict pfmt,
>     sys->format = fmt.i_format;
>     sys->block_align = pwf->nBlockAlign;
>     sys->rate = pwf->nSamplesPerSec;
>+    sys->s24s32 = pwf->wBitsPerSample == 24 && fmt.i_format ==
>VLC_CODEC_S32N;
>+    if (sys->s24s32)
>+        msg_Dbg(s, "audio device configured as s24");
> 
>hr = IAudioClient_Initialize(sys->client, shared_mode, 0,
>buffer_duration,
>                                  0, pwf, sid);
>-- 
>2.20.1
>
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