[FFmpeg-cvslog] af_hdcd: Warn if there is any resampling or format conversion in the link chain

[Burt P]

ffmpeg | branch: master | Burt P <pburt0 at gmail.com> | Fri Jul 29 12:36:22 2016 -0500| [bea17a3d57053e77a9b3f46291f9d620dd76f7a2] | committer: Michael Niedermayer

af_hdcd: Warn if there is any resampling or format conversion in the link chain

HDCD is only encoded in s16 at 44100Hz. Scan the chain of AVFilterLinks
for any resampling or format conversion/truncation that might cause
problems for the filter and issue warnings.

Signed-off-by: Burt P <pburt0 at gmail.com>
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=bea17a3d57053e77a9b3f46291f9d620dd76f7a2
---

 libavfilter/af_hdcd.c | 62 +++++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 58 insertions(+), 4 deletions(-)

diff --git a/libavfilter/af_hdcd.c b/libavfilter/af_hdcd.c
index 683c588..2ca2950 100644
--- a/libavfilter/af_hdcd.c
+++ b/libavfilter/af_hdcd.c
@@ -885,6 +885,11 @@ typedef struct HDCDContext {
      * default is off */
     int force_pe;
 
+    /* config_input() and config_output() scan links for any resampling
+     * or format changes. If found, warnings are issued and bad_config
+     * is set. */
+    int bad_config;
+
     AVFilterContext *fctx; /* filter context for logging errors */
     int sample_count;      /* used in error logging */
     int val_target_gain;   /* last matching target_gain in both channels */
@@ -1519,25 +1524,29 @@ static av_cold void uninit(AVFilterContext *ctx)
     /* log the HDCD decode information */
     if (s->hdcd_detected)
         av_log(ctx, AV_LOG_INFO,
-            "HDCD detected: yes, peak_extend: %s, max_gain_adj: %0.1f dB, transient_filter: %s, detectable errors: %d%s\n",
+            "HDCD detected: yes, peak_extend: %s, max_gain_adj: %0.1f dB, transient_filter: %s, detectable errors: %d%s%s\n",
             pe_str[s->peak_extend],
             s->max_gain_adjustment,
             (s->uses_transient_filter) ? "detected" : "not detected",
-            s->det_errors, (s->det_errors) ? " (try -v verbose)" : ""
+            s->det_errors, (s->det_errors) ? " (try -v verbose)" : "",
+            (s->bad_config) ? " (bad_config)" : ""
             );
     else
-        av_log(ctx, AV_LOG_INFO, "HDCD detected: no\n");
+        av_log(ctx, AV_LOG_INFO, "HDCD detected: no%s\n",
+            (s->bad_config) ? " (bad_config)" : ""
+            );
 }
 
+
 static av_cold int init(AVFilterContext *ctx)
 {
-
     HDCDContext *s = ctx->priv;
     int c;
 
     s->max_gain_adjustment = 0.0;
     s->sample_count = 0;
     s->fctx = ctx;
+    s->bad_config = 0;
 
     for (c = 0; c < HDCD_MAX_CHANNELS; c++) {
         hdcd_reset(&s->state[c], 44100);
@@ -1551,19 +1560,64 @@ static av_cold int init(AVFilterContext *ctx)
     return 0;
 }
 
+static int config_input(AVFilterLink *inlink) {
+    AVFilterContext *ctx = inlink->dst;
+    HDCDContext *s = ctx->priv;
+    AVFilterLink *lk = inlink;
+    while(lk != NULL) {
+        AVFilterContext *nextf = lk->src;
+        if (lk->format != AV_SAMPLE_FMT_S16 || lk->sample_rate != 44100) {
+            av_log(ctx, AV_LOG_WARNING, "An input format is %s@%dHz at %s. It will truncated/resampled to s16 at 44100Hz.\n",
+                av_get_sample_fmt_name(lk->format), lk->sample_rate,
+                (nextf->name) ? nextf->name : "<unknown>"
+                );
+            s->bad_config = 1;
+            break;
+        }
+        lk = (nextf->inputs) ? nextf->inputs[0] : NULL;
+    }
+    /* more warning will appear after config_output() */
+    return 0;
+}
+
 static const AVFilterPad avfilter_af_hdcd_inputs[] = {
     {
         .name         = "default",
         .type         = AVMEDIA_TYPE_AUDIO,
         .filter_frame = filter_frame,
+        .config_props = config_input,
     },
     { NULL }
 };
 
+static int config_output(AVFilterLink *outlink) {
+    static const char hdcd_baduse[] =
+        "The HDCD filter is unlikely to produce a desirable result in this context.";
+    AVFilterContext *ctx = outlink->src;
+    HDCDContext *s = ctx->priv;
+    AVFilterLink *lk = outlink;
+    while(lk != NULL) {
+        AVFilterContext *nextf = lk->dst;
+        if (lk->format == AV_SAMPLE_FMT_S16 || lk->format == AV_SAMPLE_FMT_U8) {
+            av_log(ctx, AV_LOG_WARNING, "s24 output is being truncated to %s at %s. (Try -f s24le after the filter)\n",
+                av_get_sample_fmt_name(lk->format),
+                (nextf->name) ? nextf->name : "<unknown>"
+                );
+            s->bad_config = 1;
+            break;
+        }
+        lk = (nextf->outputs) ? nextf->outputs[0] : NULL;
+    }
+    if (s->bad_config)
+        av_log(ctx, AV_LOG_WARNING, "%s\n", hdcd_baduse);
+    return 0;
+}
+
 static const AVFilterPad avfilter_af_hdcd_outputs[] = {
     {
         .name = "default",
         .type = AVMEDIA_TYPE_AUDIO,
+        .config_props = config_output,
     },
     { NULL }
 };