fftools/ffmpeg: stop accessing input format from decoding code

Export the corresponding flag in InputFile instead. This will allow
making the demuxer AVFormatContext private in future commits, similarly
to what was previously done for muxers.

fftools/ffmpeg.c

@@ -976,7 +976,6 @@ static int decode_audio(InputStream *ist, const AVPacket *pkt, int *got_output,
 static int64_t video_duration_estimate(const InputStream *ist, const AVFrame *frame)
 {
     const InputFile   *ifile = input_files[ist->file_index];
-    const int container_nots = !!(ifile->ctx->iformat->flags & AVFMT_NOTIMESTAMPS);
     int64_t codec_duration = 0;
 
     // XXX lavf currently makes up frame durations when they are not provided by
@@ -986,7 +985,7 @@ static int64_t video_duration_estimate(const InputStream *ist, const AVFrame *fr
     // durations, then this should be simplified.
 
     // prefer frame duration for containers with timestamps
-    if (frame->duration > 0 && !container_nots)
+    if (frame->duration > 0 && !ifile->format_nots)
         return frame->duration;
 
     if (ist->dec_ctx->framerate.den && ist->dec_ctx->framerate.num) {
@@ -998,7 +997,7 @@ static int64_t video_duration_estimate(const InputStream *ist, const AVFrame *fr
     }
 
     // prefer codec-layer duration for containers without timestamps
-    if (codec_duration > 0 && container_nots)
+    if (codec_duration > 0 && ifile->format_nots)
         return codec_duration;
 
     // when timestamps are available, repeat last frame's actual duration

fftools/ffmpeg.h

@@ -442,6 +442,9 @@ typedef struct InputFile {
 
     int index;
 
+    // input format has no timestamps
+    int format_nots;
+
     AVFormatContext *ctx;
     int eof_reached;      /* true if eof reached */
     int eagain;           /* true if last read attempt returned EAGAIN */

fftools/ffmpeg_demux.c

@@ -1504,6 +1504,8 @@ int ifile_open(const OptionsContext *o, const char *filename)
     d->duration = 0;
     d->time_base = (AVRational){ 1, 1 };
 
+    f->format_nots = !!(ic->iformat->flags & AVFMT_NOTIMESTAMPS);
+
     f->readrate = o->readrate ? o->readrate : 0.0;
     if (f->readrate < 0.0f) {
         av_log(d, AV_LOG_ERROR, "Option -readrate is %0.3f; it must be non-negative.\n", f->readrate);