[FFmpeg-devel] [PATCH] lavf/movdec: add position_order option

[Rodger Combs]

This allows reading packets linearly, which prevents large numbers of
unnecessary seeks in poorly-interleaved files with consumer software that
handles those cases well on its own.
---
 libavformat/isom.h    |  1 +
 libavformat/mov.c     | 11 +++++++----
 libavformat/version.h |  2 +-
 3 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/libavformat/isom.h b/libavformat/isom.h
index 69452cae8e..3e29e9877d 100644
--- a/libavformat/isom.h
+++ b/libavformat/isom.h
@@ -288,6 +288,7 @@ typedef struct MOVContext {
     int decryption_key_len;
     int enable_drefs;
     int32_t movie_display_matrix[3][3]; ///< display matrix from mvhd
+    int position_order;
 } MOVContext;
 
 int ff_mp4_read_descr_len(AVIOContext *pb);
diff --git a/libavformat/mov.c b/libavformat/mov.c
index 675b915906..a1559b8a8f 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -7626,8 +7626,10 @@ static int mov_read_header(AVFormatContext *s)
 
 static AVIndexEntry *mov_find_next_sample(AVFormatContext *s, AVStream **st)
 {
+    MOVContext *mov = s->priv_data;
     AVIndexEntry *sample = NULL;
     int64_t best_dts = INT64_MAX;
+    int use_pos = mov->position_order || !(s->pb->seekable & AVIO_SEEKABLE_NORMAL);
     int i;
     for (i = 0; i < s->nb_streams; i++) {
         AVStream *avst = s->streams[i];
@@ -7636,11 +7638,10 @@ static AVIndexEntry *mov_find_next_sample(AVFormatContext *s, AVStream **st)
             AVIndexEntry *current_sample = &avst->index_entries[msc->current_sample];
             int64_t dts = av_rescale(current_sample->timestamp, AV_TIME_BASE, msc->time_scale);
             av_log(s, AV_LOG_TRACE, "stream %d, sample %d, dts %"PRId64"\n", i, msc->current_sample, dts);
-            if (!sample || (!(s->pb->seekable & AVIO_SEEKABLE_NORMAL) && current_sample->pos < sample->pos) ||
-                ((s->pb->seekable & AVIO_SEEKABLE_NORMAL) &&
-                 ((msc->pb != s->pb && dts < best_dts) || (msc->pb == s->pb &&
+            if (!sample || (use_pos ? (current_sample->pos < sample->pos) :
+                (((msc->pb != s->pb && dts < best_dts) || (msc->pb == s->pb &&
                  ((FFABS(best_dts - dts) <= AV_TIME_BASE && current_sample->pos < sample->pos) ||
-                  (FFABS(best_dts - dts) > AV_TIME_BASE && dts < best_dts)))))) {
+                  (FFABS(best_dts - dts) > AV_TIME_BASE && dts < best_dts))))))) {
                 sample = current_sample;
                 best_dts = dts;
                 *st = avst;
@@ -8017,6 +8018,8 @@ static const AVOption mov_options[] = {
     { "decryption_key", "The media decryption key (hex)", OFFSET(decryption_key), AV_OPT_TYPE_BINARY, .flags = AV_OPT_FLAG_DECODING_PARAM },
     { "enable_drefs", "Enable external track support.", OFFSET(enable_drefs), AV_OPT_TYPE_BOOL,
         {.i64 = 0}, 0, 1, FLAGS },
+    { "position_order", "Read packets in position order (rather than timestamp order)",
+        OFFSET(position_order), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, FLAGS },
 
     { NULL },
 };
diff --git a/libavformat/version.h b/libavformat/version.h
index edfa73fb97..2eb14659d0 100644
--- a/libavformat/version.h
+++ b/libavformat/version.h
@@ -33,7 +33,7 @@
 // Also please add any ticket numbers that you believe might be affected here
 #define LIBAVFORMAT_VERSION_MAJOR  58
 #define LIBAVFORMAT_VERSION_MINOR  32
-#define LIBAVFORMAT_VERSION_MICRO 104
+#define LIBAVFORMAT_VERSION_MICRO 105
 
 #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \
                                                LIBAVFORMAT_VERSION_MINOR, \
-- 
2.21.0