From 0cdbc6db6ea1ee6cdeedec6c8bd84e692d5f82d3 Mon Sep 17 00:00:00 2001
From: wm4 <wm4@nowhere>
Date: Sat, 16 Nov 2013 20:51:05 +0100
Subject: [PATCH] demux_lavf: remove broken and commented byte based seeks

This was originally added for better seeking where libavformat's seek
function won't work well: files with timestamp resets. In these cases,
the code tried to calculate an average bitrate, and then do byte based
seeks by multiplying the seek target time with the bitrate.

Apparently this was unreliable enough that the code was just commented
(and other parts became inactive). Get rid of it.

Note that the player still does byte based seeks in these cases when
doing percent-seeks.
---
 demux/demux_lavf.c | 40 ----------------------------------------
 1 file changed, 40 deletions(-)

diff --git a/demux/demux_lavf.c b/demux/demux_lavf.c
index b2dfcb2193..946c76fb84 100644
--- a/demux/demux_lavf.c
+++ b/demux/demux_lavf.c
@@ -83,8 +83,6 @@ typedef struct lavf_priv {
     int num_streams;
     int cur_program;
     bool use_dts;
-    bool seek_by_bytes;
-    int bitrate;
     char *mime_type;
     bool genpts_hack;
     AVPacket *packets[MAX_PKT_QUEUE];
@@ -685,27 +683,6 @@ static int demux_open_lavf(demuxer_t *demuxer, enum demux_check check)
 
     demuxer->ts_resets_possible = priv->avif->flags & AVFMT_TS_DISCONT;
 
-    // disabled because unreliable per-stream bitrate values returned
-    // by libavformat trigger this heuristic incorrectly and break things
-#if 0
-    /* libavformat sets bitrate for mpeg based on pts at start and end
-     * of file, which fails for files with pts resets. So calculate our
-     * own bitrate estimate. */
-    if (priv->avif->flags & AVFMT_TS_DISCONT) {
-        for (int i = 0; i < avfc->nb_streams; i++)
-            priv->bitrate += avfc->streams[i]->codec->bit_rate;
-        /* pts-based is more accurate if there are no resets; try to make
-         * a somewhat reasonable guess */
-        if (!avfc->duration || avfc->duration == AV_NOPTS_VALUE
-            || priv->bitrate && (avfc->bit_rate < priv->bitrate / 2
-                                 || avfc->bit_rate > priv->bitrate * 2))
-            priv->seek_by_bytes = true;
-        if (!priv->bitrate)
-            priv->bitrate = 1440000;
-    }
-#endif
-    demuxer->accurate_seek = !priv->seek_by_bytes;
-
     return 0;
 }
 
@@ -839,14 +816,6 @@ static void demux_seek_lavf(demuxer_t *demuxer, float rel_seek_secs, int flags)
 
     seek_reset(demuxer);
 
-    if (priv->seek_by_bytes) {
-        int64_t pos = demuxer->filepos;
-        rel_seek_secs *= priv->bitrate / 8;
-        pos += rel_seek_secs;
-        av_seek_frame(priv->avfc, -1, pos, AVSEEK_FLAG_BYTE);
-        return;
-    }
-
     if (flags & SEEK_ABSOLUTE)
         priv->last_pts = 0;
     else if (rel_seek_secs < 0)
@@ -923,15 +892,6 @@ static int demux_lavf_control(demuxer_t *demuxer, int cmd, void *arg)
 
     switch (cmd) {
     case DEMUXER_CTRL_GET_TIME_LENGTH:
-        if (priv->seek_by_bytes) {
-            struct stream *s = demuxer->stream;
-            /* Our bitrate estimate may be better than would be used in
-             * otherwise similar fallback code at higher level */
-            if (s->end_pos <= 0)
-                return DEMUXER_CTRL_DONTKNOW;
-            *(double *)arg = (s->end_pos - s->start_pos) * 8 / priv->bitrate;
-            return DEMUXER_CTRL_GUESS;
-        }
         if (priv->avfc->duration == 0 || priv->avfc->duration == AV_NOPTS_VALUE)
             return DEMUXER_CTRL_DONTKNOW;