RepoMirrors/mpv
1
0
Fork 0
mirror of https://github.com/mpv-player/mpv synced 2025-04-04 23:40:47 +00:00
Code Issues Releases Wiki Activity

demux_lavf: add terrible hack to make DVD playback just work

Browse Source 
DVD playback had some trouble with PTS resets: libavformat's genpts
feature would try reading until EOF (worst case) to find a new usable
PTS in case a packet's PTS is not set correctly. Especially with slow
DVD access, this would make the player to appear frozen.

Reimplement it partially in demux_lavf.c, and use that code in the DVD
case. This is heavily "inspired" by the code in av_read_frame from
libavformat/utils.c. The difference is that we stop reading if no PTS
has been found after 50 packets (consider this a heuristic). Also, we
don't bother with the PTS wrapping and last-frame-before-EOF handling.
Even with normal PTS wraps, the player frontend will go to hell for the
duration of a frame anyway, and should recover quickly after that.

The terribleness of this commit is mostly that we duplicate libavformat
functionality, and that we suddenly need a packet queue.
This commit is contained in:
wm4 2013-07-14 23:44:50 +02:00
parent e18ffd6b99
commit 65d8709152
3 changed files with 111 additions and 23 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
DOCS/man/en/options.rst
View File

@ -559,6 +559,16 @@
``--demuxer-lavf-format=<value>``
Force a specific libavformat demuxer.
``--demuxer-lavf-genpts-mode=<auto|lavf|builtin|no>``
Mode for deriving missing packet PTS values from packet DTS. ``lavf``
enables libavformat's ``genpts`` option. ``builtin`` enables equivalent
code in mpv. ``auto`` will enable either lavf (normal playback) or builtin
(DVD playback) in correct-pts mode. The difference between them is that
the builtin code will not potentially read until EOF trying to derive the
PTS (which is very bad for DVD playback). On the other hand, builtin might
give up too early, which is why lavf is preferred normally. ``no`` disables
both.
``--demuxer-lavf-o=<key>=<value>[,<key>=<value>[,...]]``
Pass AVOptions to libavformat demuxer.

1
core/options.h
View File

@ -223,6 +223,7 @@ typedef struct MPOpts {
char *format;
char *cryptokey;
char *avopt;
int genptsmode;
} lavfdopts;
struct input_conf {

123
demux/demux_lavf.c
View File

@ -58,6 +58,8 @@ const m_option_t lavfdopts_conf[] = {
OPT_FLAG("allow-mimetype", lavfdopts.allow_mimetype, 0),
OPT_INTRANGE("probescore", lavfdopts.probescore, 0, 0, 100),
OPT_STRING("cryptokey", lavfdopts.cryptokey, 0),
OPT_CHOICE("genpts-mode", lavfdopts.genptsmode, 0,
({"auto", 0}, {"lavf", 1}, {"builtin", 2}, {"no", 3})),
OPT_STRING("o", lavfdopts.avopt, 0),
{NULL, NULL, 0, 0, 0, 0, NULL}
};
@ -66,6 +68,8 @@ const m_option_t lavfdopts_conf[] = {
// libavformat (almost) always reads data in blocks of this size.
#define BIO_BUFFER_SIZE 32768
#define MAX_PKT_QUEUE 50
typedef struct lavf_priv {
char *filename;
const struct format_hack *format_hack;
@ -81,6 +85,9 @@ typedef struct lavf_priv {
bool seek_by_bytes;
int bitrate;
char *mime_type;
bool genpts_hack;
AVPacket *packets[MAX_PKT_QUEUE];
int num_packets;
} lavf_priv_t;
struct format_hack {
@ -522,8 +529,13 @@ static int demux_open_lavf(demuxer_t *demuxer, enum demux_check check)
priv->use_dts = true;
demuxer->timestamp_type = TIMESTAMP_TYPE_SORT;
} else {
if (opts->user_correct_pts != 0)
int mode = lavfdopts->genptsmode;
if (mode == 0 && opts->user_correct_pts != 0)
mode = demuxer->stream->uncached_type == STREAMTYPE_DVD ? 2 : 1;
if (mode == 1)
avfc->flags |= AVFMT_FLAG_GENPTS;
if (mode == 2)
priv->genpts_hack = true;
}
if (opts->index_mode == 0)
avfc->flags |= AVFMT_FLAG_IGNIDX;
@ -646,45 +658,107 @@ static int demux_open_lavf(demuxer_t *demuxer, enum demux_check check)
return 0;
}
static void seek_reset(demuxer_t *demux)
{
lavf_priv_t *priv = demux->priv;
for (int n = 0; n < priv->num_packets; n++)
talloc_free(priv->packets[n]);
priv->num_packets = 0;
}
static int destroy_avpacket(void *pkt)
{
av_free_packet(pkt);
return 0;
}
static int read_more_av_packets(demuxer_t *demux)
{
lavf_priv_t *priv = demux->priv;
if (priv->num_packets >= MAX_PKT_QUEUE)
return -1;
demux->filepos = stream_tell(demux->stream);
AVPacket *pkt = talloc(NULL, AVPacket);
if (av_read_frame(priv->avfc, pkt) < 0) {
talloc_free(pkt);
return -2; // eof
}
talloc_set_destructor(pkt, destroy_avpacket);
add_new_streams(demux);
assert(pkt->stream_index >= 0 && pkt->stream_index < priv->num_streams);
struct sh_stream *stream = priv->streams[pkt->stream_index];
if (!demuxer_stream_is_selected(demux, stream)) {
talloc_free(pkt);
return 0; // skip
}
// If the packet has pointers to temporary fields that could be
// overwritten/freed by next av_read_frame(), copy them to persistent
// allocations so we can safely queue the packet for any length of time.
if (av_dup_packet(pkt) < 0)
abort();
priv->packets[priv->num_packets++] = pkt;
talloc_steal(priv, pkt);
return 1;
}
static int read_av_packet(demuxer_t *demux, AVPacket **pkt)
{
lavf_priv_t *priv = demux->priv;
if (priv->num_packets < 1) {
int r = read_more_av_packets(demux);
if (r <= 0)
return r;
}
AVPacket *next = priv->packets[0];
if (priv->genpts_hack && next->dts != AV_NOPTS_VALUE) {
int n = 1;
while (next->pts == AV_NOPTS_VALUE) {
while (n >= priv->num_packets) {
if (read_more_av_packets(demux) < 0)
goto end; // queue limit or EOF reached - just use as is
}
AVPacket *cur = priv->packets[n];
if (cur->stream_index == next->stream_index) {
if (next->dts < cur->dts && cur->pts != cur->dts)
next->pts = cur->dts;
}
n++;
}
}
end:
MP_TARRAY_REMOVE_AT(priv->packets, priv->num_packets, 0);
*pkt = next;
return 1;
}
static int demux_lavf_fill_buffer(demuxer_t *demux)
{
lavf_priv_t *priv = demux->priv;
demux_packet_t *dp;
mp_msg(MSGT_DEMUX, MSGL_DBG2, "demux_lavf_fill_buffer()\n");
demux->filepos = stream_tell(demux->stream);
AVPacket *pkt;
int r = read_av_packet(demux, &pkt);
if (r <= 0)
return r == 0; // don't signal EOF if skipping a packet
AVPacket *pkt = talloc(NULL, AVPacket);
if (av_read_frame(priv->avfc, pkt) < 0) {
talloc_free(pkt);
return 0;
}
talloc_set_destructor(pkt, destroy_avpacket);
add_new_streams(demux);
assert(pkt->stream_index >= 0 && pkt->stream_index < priv->num_streams);
AVStream *st = priv->avfc->streams[pkt->stream_index];
struct sh_stream *stream = priv->streams[pkt->stream_index];
if (!demuxer_stream_is_selected(demux, stream)) {
talloc_free(pkt);
return 1;
}
// If the packet has pointers to temporary fields that could be
// overwritten/freed by next av_read_frame(), copy them to persistent
// allocations so we can safely queue the packet for any length of time.
if (av_dup_packet(pkt) < 0)
abort();
dp = new_demux_packet_fromdata(pkt->data, pkt->size);
dp->avpacket = pkt;
dp->avpacket = talloc_steal(dp, pkt);
int64_t ts = priv->use_dts ? pkt->dts : pkt->pts;
if (ts != AV_NOPTS_VALUE) {
@ -714,6 +788,8 @@ static void demux_seek_lavf(demuxer_t *demuxer, float rel_seek_secs,
mp_msg(MSGT_DEMUX, MSGL_DBG2, "demux_seek_lavf(%p, %f, %f, %d)\n",
demuxer, rel_seek_secs, audio_delay, flags);
seek_reset(demuxer);
if (priv->seek_by_bytes) {
int64_t pos = demuxer->filepos;
rel_seek_secs *= priv->bitrate / 8;
@ -877,6 +953,7 @@ redo:
avio_flush(priv->avfc->pb);
av_seek_frame(priv->avfc, 0, stream_tell(demuxer->stream),
AVSEEK_FLAG_BYTE);
seek_reset(demuxer);
avio_flush(priv->avfc->pb);
return DEMUXER_CTRL_OK;
default: