fftools/ffmpeg_dec: move InputStream.pkt to Decoder

It is purely internal to decoding.

fftools/ffmpeg.h

@@ -349,7 +349,6 @@ typedef struct InputStream {
     AVCodecContext *dec_ctx;
     const AVCodec *dec;
     const AVCodecDescriptor *codec_desc;
-    AVPacket *pkt;
 
     AVRational framerate_guessed;
 

fftools/ffmpeg_dec.c

@@ -33,6 +33,7 @@
 
 struct Decoder {
     AVFrame         *frame;
+    AVPacket        *pkt;
 };
 
 void dec_free(Decoder **pdec)
@@ -43,6 +44,7 @@ void dec_free(Decoder **pdec)
         return;
 
     av_frame_free(&dec->frame);
+    av_packet_free(&dec->pkt);
 
     av_freep(pdec);
 }
@@ -61,6 +63,10 @@ static int dec_alloc(Decoder **pdec)
     if (!dec->frame)
         goto fail;
 
+    dec->pkt = av_packet_alloc();
+    if (!dec->pkt)
+        goto fail;
+
 
     *pdec = dec;
 
@@ -418,7 +424,7 @@ int dec_packet(InputStream *ist, const AVPacket *pkt, int no_eof)
     int ret;
 
     if (dec->codec_type == AVMEDIA_TYPE_SUBTITLE)
-        return transcode_subtitles(ist, pkt ? pkt : ist->pkt);
+        return transcode_subtitles(ist, pkt ? pkt : d->pkt);
 
     // With fate-indeo3-2, we're getting 0-sized packets before EOF for some
     // reason. This seems like a semi-critical bug. Don't trigger EOF, and

fftools/ffmpeg_demux.c

@@ -817,7 +817,6 @@ static void ist_free(InputStream **pist)
 
     dec_free(&ist->decoder);
 
-    av_packet_free(&ist->pkt);
     av_dict_free(&ist->decoder_opts);
     avsubtitle_free(&ist->prev_sub.subtitle);
     av_frame_free(&ist->sub2video.frame);
@@ -1197,10 +1196,6 @@ static void add_input_streams(const OptionsContext *o, Demuxer *d)
             exit_program(1);
         }
 
-        ist->pkt = av_packet_alloc();
-        if (!ist->pkt)
-            report_and_exit(AVERROR(ENOMEM));
-
         if (o->bitexact)
             ist->dec_ctx->flags |= AV_CODEC_FLAG_BITEXACT;