Remove remains of Libav compatibility

Libav seems rather dead: no release for 2 years, no new git commits in
master for almost a year (with one exception ~6 months ago). From what I
can tell, some developers resigned themselves to the horrifying idea to
post patches to ffmpeg-devel instead, while the rest of the developers
went on to greener pastures.

Libav was a better project than FFmpeg. Unfortunately, FFmpeg won,
because it managed to keep the name and website. Libav was pushed more
and more into obscurity: while there was initially a big push for Libav,
FFmpeg just remained "in place" and visible for most people. FFmpeg was
slowly draining all manpower and energy from Libav. A big part of this
was that FFmpeg stole code from Libav (regular merges of the entire
Libav git tree), making it some sort of Frankenstein mirror of Libav,
think decaying zombie with additional legs ("features") nailed to it.
"Stealing" surely is the wrong word; I'm just aping the language that
some of the FFmpeg members used to use. All that is in the past now, I'm
probably the only person left who is annoyed by this, and with this
commit I'm putting this decade long problem finally to an end. I just
thought I'd express my annoyance about this fucking shitshow one last
time.

The most intrusive change in this commit is the resample filter, which
originally used libavresample. Since the FFmpeg developer refused to
enable libavresample by default for drama reasons, and the API was
slightly different, so the filter used some big preprocessor mess to
make it compatible to libswresample. All that falls away now. The
simplification to the build system is also significant.

2 files changed, 15 insertions, 75 deletions

diff --git a/filters/f_lavfi.c b/filters/f_lavfi.c
index db01e27e3e..18bad4b5f4 100644
--- a/filters/f_lavfi.c
+++ b/filters/f_lavfi.c
@@ -50,11 +50,6 @@
 #include "filter_internal.h"
 #include "user_filters.h"
 
-#if LIBAVFILTER_VERSION_MICRO < 100
-#define av_buffersink_get_frame_flags(a, b, c) av_buffersink_get_frame(a, b)
-#define AV_BUFFERSINK_FLAG_NO_REQUEST 0
-#endif
-
 struct lavfi {
     struct mp_log *log;
     struct mp_filter *f;
@@ -529,13 +524,11 @@ error:
 
 static void dump_graph(struct lavfi *c)
 {
-#if LIBAVFILTER_VERSION_MICRO >= 100
     MP_DBG(c, "Filter graph:\n");
     char *s = avfilter_graph_dump(c->graph, NULL);
     if (s)
         MP_DBG(c, "%s\n", s);
     av_free(s);
-#endif
 }
 
 // Initialize the graph if all inputs have formats set. If it's already
@@ -591,10 +584,7 @@ static bool feed_input_pads(struct lavfi *c)
     for (int n = 0; n < c->num_in_pads; n++) {
         struct lavfi_pad *pad = c->in_pads[n];
 
-        bool requested = true;
-#if LIBAVFILTER_VERSION_MICRO >= 100
-        requested = av_buffersrc_get_nb_failed_requests(pad->buffer) > 0;
-#endif
+        bool requested = av_buffersrc_get_nb_failed_requests(pad->buffer) > 0;
 
         // Always request a frame after EOF so that we can know if the EOF state
         // changes (e.g. for sparse streams with midstream EOF).
@@ -705,9 +695,7 @@ static bool read_output_pads(struct lavfi *c)
         }
 
         if (r >= 0) {
-#if LIBAVUTIL_VERSION_MICRO >= 100
             mp_tags_copy_from_av_dictionary(pad->metadata, c->tmp_frame->metadata);
-#endif
             struct mp_frame frame =
                 mp_frame_from_av(pad->type, c->tmp_frame, &pad->timebase);
             if (c->emulate_audio_pts && frame.type == MP_FRAME_AUDIO) {
@@ -807,12 +795,10 @@ static bool lavfi_command(struct mp_filter *f, struct mp_filter_command *cmd)
         return false;
 
     switch (cmd->type) {
-#if LIBAVFILTER_VERSION_MICRO >= 100
     case MP_FILTER_COMMAND_TEXT: {
         return avfilter_graph_send_command(c->graph, "all", cmd->cmd, cmd->arg,
                                            &(char){0}, 0, 0) >= 0;
     }
-#endif
     case MP_FILTER_COMMAND_GET_META: {
         // We can worry later about what it should do to multi output filters.
         if (c->num_out_pads < 1)
diff --git a/filters/f_swresample.c b/filters/f_swresample.c
index 8ee44195a8..0f4033b26a 100644
--- a/filters/f_swresample.c
+++ b/filters/f_swresample.c
@@ -20,6 +20,7 @@
 #include <libavutil/samplefmt.h>
 #include <libavutil/channel_layout.h>
 #include <libavutil/mathematics.h>
+#include <libswresample/swresample.h>
 
 #include "config.h"
 
@@ -35,35 +36,14 @@
 #include "f_swresample.h"
 #include "filter_internal.h"
 
-#define HAVE_LIBSWRESAMPLE (!HAVE_LIBAV)
-#define HAVE_LIBAVRESAMPLE HAVE_LIBAV
-
-#if HAVE_LIBAVRESAMPLE
-#include <libavresample/avresample.h>
-#elif HAVE_LIBSWRESAMPLE
-#include <libswresample/swresample.h>
-#define AVAudioResampleContext SwrContext
-#define avresample_alloc_context swr_alloc
-#define avresample_open swr_init
-#define avresample_close(x) do { } while(0)
-#define avresample_free swr_free
-#define avresample_available(x) 0
-#define avresample_convert(ctx, out, out_planesize, out_samples, in, in_planesize, in_samples) \
-    swr_convert(ctx, out, out_samples, (const uint8_t**)(in), in_samples)
-#define avresample_set_channel_mapping swr_set_channel_mapping
-#define avresample_set_compensation swr_set_compensation
-#else
-#error "config.h broken or no resampler found"
-#endif
-
 struct priv {
     struct mp_log *log;
     bool is_resampling;
-    struct AVAudioResampleContext *avrctx;
+    struct SwrContext *avrctx;
     struct mp_aframe *avrctx_fmt; // output format of avrctx
     struct mp_aframe *pool_fmt; // format used to allocate frames for avrctx output
     struct mp_aframe *pre_out_fmt; // format before final conversion
-    struct AVAudioResampleContext *avrctx_out; // for output channel reordering
+    struct SwrContext *avrctx_out; // for output channel reordering
     struct mp_resample_opts *opts; // opts requested by the user
     // At least libswresample keeps a pointer around for this:
     int reorder_in[MP_NUM_CHANNELS];
@@ -106,17 +86,6 @@ const struct m_sub_options resample_conf = {
     .change_flags = UPDATE_AUDIO,
 };
 
-#if HAVE_LIBAVRESAMPLE
-static double get_delay(struct priv *p)
-{
-    return avresample_get_delay(p->avrctx) / (double)p->in_rate +
-           avresample_available(p->avrctx) / (double)p->out_rate;
-}
-static int get_out_samples(struct priv *p, int in_samples)
-{
-    return avresample_get_out_samples(p->avrctx, in_samples);
-}
-#else
 static double get_delay(struct priv *p)
 {
     int64_t base = p->in_rate * (int64_t)p->out_rate;
@@ -126,16 +95,11 @@ static int get_out_samples(struct priv *p, int in_samples)
 {
     return swr_get_out_samples(p->avrctx, in_samples);
 }
-#endif
 
 static void close_lavrr(struct priv *p)
 {
-    if (p->avrctx)
-        avresample_close(p->avrctx);
-    avresample_free(&p->avrctx);
-    if (p->avrctx_out)
-        avresample_close(p->avrctx_out);
-    avresample_free(&p->avrctx_out);
+    swr_free(&p->avrctx);
+    swr_free(&p->avrctx_out);
 
     TA_FREEP(&p->pre_out_fmt);
     TA_FREEP(&p->avrctx_fmt);
@@ -206,8 +170,8 @@ static bool configure_lavrr(struct priv *p, bool verbose)
                p->out_rate, mp_chmap_to_str(&p->out_channels),
                af_fmt_to_str(p->out_format));
 
-    p->avrctx = avresample_alloc_context();
-    p->avrctx_out = avresample_alloc_context();
+    p->avrctx = swr_alloc();
+    p->avrctx_out = swr_alloc();
     if (!p->avrctx || !p->avrctx_out)
         goto error;
 
@@ -234,11 +198,7 @@ static bool configure_lavrr(struct priv *p, bool verbose)
     av_opt_set_double(p->avrctx, "cutoff",          cutoff, 0);
 
     int normalize = p->opts->normalize;
-#if HAVE_LIBSWRESAMPLE
     av_opt_set_double(p->avrctx, "rematrix_maxval", normalize ? 1 : 1000, 0);
-#else
-    av_opt_set_int(p->avrctx, "normalize_mix_level", !!normalize, 0);
-#endif
 
     if (mp_set_avopts(p->log, p->avrctx, p->opts->avopts) < 0)
         goto error;
@@ -337,11 +297,11 @@ static bool configure_lavrr(struct priv *p, bool verbose)
     // API has weird requirements, quoting avresample.h:
     //  * This function can only be called when the allocated context is not open.
     //  * Also, the input channel layout must have already been set.
-    avresample_set_channel_mapping(p->avrctx, p->reorder_in);
+    swr_set_channel_mapping(p->avrctx, p->reorder_in);
 
     p->is_resampling = false;
 
-    if (avresample_open(p->avrctx) < 0 || avresample_open(p->avrctx_out) < 0) {
+    if (swr_init(p->avrctx) < 0 || swr_init(p->avrctx_out) < 0) {
         MP_ERR(p, "Cannot open Libavresample context.\n");
         goto error;
     }
@@ -363,13 +323,9 @@ static void reset(struct mp_filter *f)
 
     if (!p->avrctx)
         return;
-#if HAVE_LIBSWRESAMPLE
     swr_close(p->avrctx);
     if (swr_init(p->avrctx) < 0)
         close_lavrr(p);
-#else
-    while (avresample_read(p->avrctx, NULL, 1000) > 0) {}
-#endif
 }
 
 static void extra_output_conversion(struct mp_aframe *mpa)
@@ -428,7 +384,7 @@ static bool reorder_planes(struct mp_aframe *mpa, int *reorder,
     return true;
 }
 
-static int resample_frame(struct AVAudioResampleContext *r,
+static int resample_frame(struct SwrContext *r,
                           struct mp_aframe *out, struct mp_aframe *in,
                           int consume_in)
 {
@@ -437,12 +393,10 @@ static int resample_frame(struct AVAudioResampleContext *r,
     // or after conversion. The sample rates can also be different.
     AVFrame *av_i = in ? mp_aframe_get_raw_avframe(in) : NULL;
     AVFrame *av_o = out ? mp_aframe_get_raw_avframe(out) : NULL;
-    return avresample_convert(r,
+    return swr_convert(r,
         av_o ? av_o->extended_data : NULL,
-        av_o ? av_o->linesize[0] : 0,
         av_o ? av_o->nb_samples : 0,
-        av_i ? av_i->extended_data : NULL,
-        av_i ? av_i->linesize[0] : 0,
+        (const uint8_t **)(av_i ? av_i->extended_data : NULL),
         av_i ? MPMIN(av_i->nb_samples, consume_in) : 0);
 }
 
@@ -634,7 +588,7 @@ static void process(struct mp_filter *f)
     if (p->avrctx && use_comp) {
         AVRational r =
             av_d2q(p->speed * p->in_rate_user / p->in_rate, INT_MAX / 2);
-        // Essentially, swr/avresample_set_compensation() does 2 things:
+        // Essentially, swr_set_compensation() does 2 things:
         // - adjust output sample rate by sample_delta/compensation_distance
         // - reset the adjustment after compensation_distance output samples
         // Increase the compensation_distance to avoid undesired reset
@@ -644,7 +598,7 @@ static void process(struct mp_filter *f)
         r = (AVRational){ r.num * mult, r.den * mult };
         if (r.den == r.num)
             r = (AVRational){0}; // fully disable
-        if (avresample_set_compensation(p->avrctx, r.den - r.num, r.den) >= 0) {
+        if (swr_set_compensation(p->avrctx, r.den - r.num, r.den) >= 0) {
             exact_rate = true;
             p->is_resampling = true; // libswresample can auto-enable it
         }