avcodec/decode: Set KEY flag+pict_type generically for intra-only codecs

This commit is the analog of 3f11eac7
for decoding: It sets the AV_FRAME_FLAG_KEY and (for video decoders)
also pict_type to AV_PICTURE_TYPE_I. It furthermore stops setting
audio frames as always being key frames -- it is wrong for e.g.
TrueHD/MLP. The latter also affects TAK and DFPWM.

The change already improves output for several decoders where
it has been forgotten to set e.g. pict_type like speedhq, wnv1
or tiff. The latter is the reason for the change to the exif-image-tiff
FATE test reference file.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

libavcodec/decode.c

@@ -57,6 +57,20 @@
 typedef struct DecodeContext {
     AVCodecInternal avci;
 
+    /**
+     * This is set to AV_FRAME_FLAG_KEY for decoders of intra-only formats
+     * (those whose codec descriptor has AV_CODEC_PROP_INTRA_ONLY set)
+     * to set the flag generically.
+     */
+    int intra_only_flag;
+
+    /**
+     * This is set to AV_PICTURE_TYPE_I for intra only video decoders
+     * and to AV_PICTURE_TYPE_NONE for other decoders. It is used to set
+     * the AVFrame's pict_type before the decoder receives it.
+     */
+    enum AVPictureType initial_pict_type;
+
     /* to prevent infinite loop on errors when draining */
     int nb_draining_errors;
 
@@ -382,6 +396,7 @@ static int discard_samples(AVCodecContext *avctx, AVFrame *frame, int64_t *disca
 static inline int decode_simple_internal(AVCodecContext *avctx, AVFrame *frame, int64_t *discarded_samples)
 {
     AVCodecInternal   *avci = avctx->internal;
+    DecodeContext     *dc = decode_ctx(avci);
     AVPacket     *const pkt = avci->in_pkt;
     const FFCodec *const codec = ffcodec(avctx->codec);
     int got_frame, consumed;
@@ -409,6 +424,8 @@ static inline int decode_simple_internal(AVCodecContext *avctx, AVFrame *frame,
     if (HAVE_THREADS && avctx->active_thread_type & FF_THREAD_FRAME) {
         consumed = ff_thread_decode_frame(avctx, frame, &got_frame, pkt);
     } else {
+        frame->pict_type = dc->initial_pict_type;
+        frame->flags    |= dc->intra_only_flag;
         consumed = codec->cb.decode(avctx, frame, &got_frame, pkt);
 
         if (!(codec->caps_internal & FF_CODEC_CAP_SETS_PKT_DTS))
@@ -598,6 +615,8 @@ static int decode_receive_frame_internal(AVCodecContext *avctx, AVFrame *frame)
     av_assert0(!frame->buf[0]);
 
     if (codec->cb_type == FF_CODEC_CB_TYPE_RECEIVE_FRAME) {
+        frame->pict_type = dc->initial_pict_type;
+        frame->flags    |= dc->intra_only_flag;
         ret = codec->cb.receive_frame(avctx, frame);
         emms_c();
         if (!ret) {
@@ -627,8 +646,7 @@ static int decode_receive_frame_internal(AVCodecContext *avctx, AVFrame *frame)
                 frame->width = avctx->width;
             if (!frame->height)
                 frame->height = avctx->height;
-        } else
-            frame->flags |= AV_FRAME_FLAG_KEY;
+        }
 
         ret = fill_frame_props(avctx, frame);
         if (ret < 0) {
@@ -1794,6 +1812,13 @@ int ff_decode_preinit(AVCodecContext *avctx)
     DecodeContext     *dc = decode_ctx(avci);
     int ret = 0;
 
+    dc->initial_pict_type = AV_PICTURE_TYPE_NONE;
+    if (avctx->codec_descriptor->props & AV_CODEC_PROP_INTRA_ONLY) {
+        dc->intra_only_flag = AV_FRAME_FLAG_KEY;
+        if (avctx->codec_type == AVMEDIA_TYPE_VIDEO)
+            dc->initial_pict_type = AV_PICTURE_TYPE_I;
+    }
+
     /* if the decoder init function was already called previously,
      * free the already allocated subtitle_header before overwriting it */
     av_freep(&avctx->subtitle_header);

libavcodec/pthread_frame.c

@@ -22,13 +22,11 @@
  * @see doc/multithreading.txt
  */
 
-#include "config.h"
-
 #include <stdatomic.h>
-#include <stdint.h>
 
 #include "avcodec.h"
 #include "avcodec_internal.h"
+#include "codec_desc.h"
 #include "codec_internal.h"
 #include "decode.h"
 #include "hwaccel_internal.h"
@@ -108,6 +106,10 @@ typedef struct PerThreadContext {
     int hwaccel_threadsafe;
 
     atomic_int debug_threads;       ///< Set if the FF_DEBUG_THREADS option is set.
+
+    /// The following two fields have the same semantics as the DecodeContext field
+    int intra_only_flag;
+    enum AVPictureType initial_pict_type;
 } PerThreadContext;
 
 /**
@@ -220,6 +222,8 @@ static attribute_align_arg void *frame_worker_thread(void *arg)
 
         av_frame_unref(p->frame);
         p->got_frame = 0;
+        p->frame->pict_type = p->initial_pict_type;
+        p->frame->flags    |= p->intra_only_flag;
         p->result = codec->cb.decode(avctx, p->frame, &p->got_frame, p->avpkt);
 
         if ((p->result < 0 || !p->got_frame) && p->frame->buf[0])
@@ -763,6 +767,13 @@ static av_cold int init_thread(PerThreadContext *p, int *threads_to_free,
     AVCodecContext *copy;
     int err;
 
+    p->initial_pict_type = AV_PICTURE_TYPE_NONE;
+    if (avctx->codec_descriptor->props & AV_CODEC_PROP_INTRA_ONLY) {
+        p->intra_only_flag = AV_FRAME_FLAG_KEY;
+        if (avctx->codec_type == AVMEDIA_TYPE_VIDEO)
+            p->initial_pict_type = AV_PICTURE_TYPE_I;
+    }
+
     atomic_init(&p->state, STATE_INPUT_READY);
 
     copy = av_memdup(avctx, sizeof(*avctx));

tests/ref/fate/exif-image-tiff

@@ -20,7 +20,7 @@ crop_left=0
 crop_right=0
 pix_fmt=rgb24
 sample_aspect_ratio=1:1
-pict_type=?
+pict_type=I
 interlaced_frame=0
 top_field_first=0
 repeat_pict=0