[FFmpeg-devel] [PATCH] libavdevice/decklink: 32 bit audio support

[Dave Rice]

Hi,

I tested this with my Ultrastudio Express and confirmed that I'm getting higher bit depth recordings with the abitscope filter. This patch adds an option to get 32 bit audio as an input with the decklink device (beforehand only 16 bit audio was supported). This resolves http://trac.ffmpeg.org/ticket/6708 and is partly based upon Georg Lippitisch's earlier draft at https://ffmpeg.org/pipermail/ffmpeg-devel/2015-January/167649.html.


From fbf2bd40471c8fa35374bb1a51c51a3f4f36b992 Mon Sep 17 00:00:00 2001
From: Dave Rice <dave at dericed.com>
Date: Thu, 12 Oct 2017 13:40:59 -0400
Subject: [PATCH] libavdevice/decklink: 32 bit audio support

Partially based upon Georg Lippitsch's patch at https://ffmpeg.org/pipermail/ffmpeg-devel/2015-January/167649.html.
---
 libavdevice/decklink_common.h   |  1 +
 libavdevice/decklink_common_c.h |  1 +
 libavdevice/decklink_dec.cpp    | 17 ++++++++++++++---
 libavdevice/decklink_dec_c.c    |  1 +
 4 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/libavdevice/decklink_common.h b/libavdevice/decklink_common.h
index 6b2525fb53..b6acb01bb9 100644
--- a/libavdevice/decklink_common.h
+++ b/libavdevice/decklink_common.h
@@ -97,6 +97,7 @@ struct decklink_ctx {
     int frames_buffer_available_spots;
 
     int channels;
+    int audio_depth;
 };
 
 typedef enum { DIRECTION_IN, DIRECTION_OUT} decklink_direction_t;
diff --git a/libavdevice/decklink_common_c.h b/libavdevice/decklink_common_c.h
index 5616ab32f9..368ac259e4 100644
--- a/libavdevice/decklink_common_c.h
+++ b/libavdevice/decklink_common_c.h
@@ -42,6 +42,7 @@ struct decklink_cctx {
     double preroll;
     int v210;
     int audio_channels;
+    int audio_depth;
     int duplex_mode;
     DecklinkPtsSource audio_pts_source;
     DecklinkPtsSource video_pts_source;
diff --git a/libavdevice/decklink_dec.cpp b/libavdevice/decklink_dec.cpp
index d9ac01ac91..7e97d5f064 100644
--- a/libavdevice/decklink_dec.cpp
+++ b/libavdevice/decklink_dec.cpp
@@ -771,7 +771,7 @@ HRESULT decklink_input_callback::VideoInputFrameArrived(
         av_init_packet(&pkt);
 
         //hack among hacks
-        pkt.size = audioFrame->GetSampleFrameCount() * ctx->audio_st->codecpar->channels * (16 / 8);
+        pkt.size = audioFrame->GetSampleFrameCount() * ctx->audio_st->codecpar->channels * (ctx->audio_depth / 8);
         audioFrame->GetBytes(&audioFrameBytes);
         audioFrame->GetPacketTime(&audio_pts, ctx->audio_st->time_base.den);
         pkt.pts = get_pkt_pts(videoFrame, audioFrame, wallclock, ctx->audio_pts_source, ctx->audio_st->time_base, &initial_audio_pts);
@@ -854,6 +854,7 @@ av_cold int ff_decklink_read_header(AVFormatContext *avctx)
     ctx->audio_pts_source = cctx->audio_pts_source;
     ctx->video_pts_source = cctx->video_pts_source;
     ctx->draw_bars = cctx->draw_bars;
+    ctx->audio_depth = cctx->audio_depth;
     cctx->ctx = ctx;
 
     /* Check audio channel option for valid values: 2, 8 or 16 */
@@ -866,6 +867,16 @@ av_cold int ff_decklink_read_header(AVFormatContext *avctx)
             av_log(avctx, AV_LOG_ERROR, "Value of channels option must be one of 2, 8 or 16\n");
             return AVERROR(EINVAL);
     }
+    
+    /* Check audio bit depth option for valid values: 16 or 32 */
+    switch (cctx->audio_depth) {
+        case 16:
+        case 32:
+            break;
+        default:
+            av_log(avctx, AV_LOG_ERROR, "Value for audio bit depth option must be either 16 or 32\n");
+            return AVERROR(EINVAL);
+    }
 
     /* List available devices. */
     if (ctx->list_devices) {
@@ -930,7 +941,7 @@ av_cold int ff_decklink_read_header(AVFormatContext *avctx)
         goto error;
     }
     st->codecpar->codec_type  = AVMEDIA_TYPE_AUDIO;
-    st->codecpar->codec_id    = AV_CODEC_ID_PCM_S16LE;
+    st->codecpar->codec_id    = cctx->audio_depth == 32 ? AV_CODEC_ID_PCM_S32LE : AV_CODEC_ID_PCM_S16LE;
     st->codecpar->sample_rate = bmdAudioSampleRate48kHz;
     st->codecpar->channels    = cctx->audio_channels;
     avpriv_set_pts_info(st, 64, 1, 1000000);  /* 64 bits pts in us */
@@ -1021,7 +1032,7 @@ av_cold int ff_decklink_read_header(AVFormatContext *avctx)
     }
 
     av_log(avctx, AV_LOG_VERBOSE, "Using %d input audio channels\n", ctx->audio_st->codecpar->channels);
-    result = ctx->dli->EnableAudioInput(bmdAudioSampleRate48kHz, bmdAudioSampleType16bitInteger, ctx->audio_st->codecpar->channels);
+    result = ctx->dli->EnableAudioInput(bmdAudioSampleRate48kHz, cctx->audio_depth == 32 ? bmdAudioSampleType32bitInteger : bmdAudioSampleType16bitInteger, ctx->audio_st->codecpar->channels);
 
     if (result != S_OK) {
         av_log(avctx, AV_LOG_ERROR, "Cannot enable audio input\n");
diff --git a/libavdevice/decklink_dec_c.c b/libavdevice/decklink_dec_c.c
index 1127d23ada..1c6d826945 100644
--- a/libavdevice/decklink_dec_c.c
+++ b/libavdevice/decklink_dec_c.c
@@ -72,6 +72,7 @@ static const AVOption options[] = {
     { "wallclock",     NULL,                                          0,  AV_OPT_TYPE_CONST, { .i64 = PTS_SRC_WALLCLOCK}, 0, 0, DEC, "pts_source"},
     { "draw_bars",     "draw bars on signal loss" , OFFSET(draw_bars),    AV_OPT_TYPE_BOOL,  { .i64 = 1}, 0, 1, DEC },
     { "queue_size",    "input queue buffer size",   OFFSET(queue_size),   AV_OPT_TYPE_INT64, { .i64 = (1024 * 1024 * 1024)}, 0, INT64_MAX, DEC },
+    { "audio_depth",   "audio bitdepth (16 or 32)", OFFSET(audio_depth),  AV_OPT_TYPE_INT,   { .i64 = 16}, 16, 32, DEC },
     { NULL },
 };
 
-- 
2.14.2


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Dave Rice