ffmpeg: Allocate InputStream.decoded_frame early

Based on a commit by Andreas Rheinhardt.

Signed-off-by: James Almer <jamrial@gmail.com>

fftools/ffmpeg.c

@@ -2332,15 +2332,11 @@ static int send_frame_to_filters(InputStream *ist, AVFrame *decoded_frame)
 static int decode_audio(InputStream *ist, AVPacket *pkt, int *got_output,
                         int *decode_failed)
 {
-    AVFrame *decoded_frame;
+    AVFrame *decoded_frame = ist->decoded_frame;
     AVCodecContext *avctx = ist->dec_ctx;
     int ret, err = 0;
     AVRational decoded_frame_tb;
 
-    if (!ist->decoded_frame && !(ist->decoded_frame = av_frame_alloc()))
-        return AVERROR(ENOMEM);
-    decoded_frame = ist->decoded_frame;
-
     update_benchmark(NULL);
     ret = decode(avctx, decoded_frame, got_output, pkt);
     update_benchmark("decode_audio %d.%d", ist->file_index, ist->st->index);
@@ -2397,7 +2393,7 @@ static int decode_audio(InputStream *ist, AVPacket *pkt, int *got_output,
 static int decode_video(InputStream *ist, AVPacket *pkt, int *got_output, int64_t *duration_pts, int eof,
                         int *decode_failed)
 {
-    AVFrame *decoded_frame;
+    AVFrame *decoded_frame = ist->decoded_frame;
     int i, ret = 0, err = 0;
     int64_t best_effort_timestamp;
     int64_t dts = AV_NOPTS_VALUE;
@@ -2408,9 +2404,6 @@ static int decode_video(InputStream *ist, AVPacket *pkt, int *got_output, int64_
     if (!eof && pkt && pkt->size == 0)
         return 0;
 
-    if (!ist->decoded_frame && !(ist->decoded_frame = av_frame_alloc()))
-        return AVERROR(ENOMEM);
-    decoded_frame = ist->decoded_frame;
     if (ist->dts != AV_NOPTS_VALUE)
         dts = av_rescale_q(ist->dts, AV_TIME_BASE_Q, ist->st->time_base);
     if (pkt) {

fftools/ffmpeg_opt.c

@@ -889,6 +889,10 @@ static void add_input_streams(OptionsContext *o, AVFormatContext *ic)
             exit_program(1);
         }
 
+        ist->decoded_frame = av_frame_alloc();
+        if (!ist->decoded_frame)
+            exit_program(1);
+
         ist->filter_frame = av_frame_alloc();
         if (!ist->filter_frame)
             exit_program(1);