ffplay.c

/*
 * Copyright (c) 2003 Fabrice Bellard
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file
 * simple media player based on the FFmpeg libraries
 */

#include "config.h"
#include <inttypes.h>
#include <math.h>
#include <limits.h>
#include <signal.h>
#include <stdint.h>

#include "libavutil/avstring.h"
#include "libavutil/colorspace.h"
#include "libavutil/mathematics.h"
#include "libavutil/pixdesc.h"
#include "libavutil/imgutils.h"
#include "libavutil/dict.h"
#include "libavutil/parseutils.h"
#include "libavutil/samplefmt.h"
#include "libavutil/avassert.h"
#include "libavutil/time.h"
#include "libavformat/avformat.h"
#include "libavdevice/avdevice.h"
#include "libswscale/swscale.h"
#include "libavutil/opt.h"
#include "libavcodec/avfft.h"
#include "libswresample/swresample.h"

#if CONFIG_AVFILTER
# include "libavfilter/avcodec.h"
# include "libavfilter/avfilter.h"
# include "libavfilter/buffersink.h"
# include "libavfilter/buffersrc.h"
#endif

#include <SDL.h>
#include <SDL_thread.h>

#include "cmdutils.h"

#include <assert.h>

const char program_name[] = "ffplay";
const int program_birth_year = 2003;

#define MAX_QUEUE_SIZE (15 * 1024 * 1024)
#define MIN_FRAMES 5

/* Minimum SDL audio buffer size, in samples. */
#define SDL_AUDIO_MIN_BUFFER_SIZE 512
/* Calculate actual buffer size keeping in mind not cause too frequent audio callbacks */
#define SDL_AUDIO_MAX_CALLBACKS_PER_SEC 30

/* no AV sync correction is done if below the minimum AV sync threshold */
#define AV_SYNC_THRESHOLD_MIN 0.04
/* AV sync correction is done if above the maximum AV sync threshold */
#define AV_SYNC_THRESHOLD_MAX 0.1
/* If a frame duration is longer than this, it will not be duplicated to compensate AV sync */
#define AV_SYNC_FRAMEDUP_THRESHOLD 0.1
/* no AV correction is done if too big error */
#define AV_NOSYNC_THRESHOLD 10.0

/* maximum audio speed change to get correct sync */
#define SAMPLE_CORRECTION_PERCENT_MAX 10

/* external clock speed adjustment constants for realtime sources based on buffer fullness */
#define EXTERNAL_CLOCK_SPEED_MIN  0.900
#define EXTERNAL_CLOCK_SPEED_MAX  1.010
#define EXTERNAL_CLOCK_SPEED_STEP 0.001

/* we use about AUDIO_DIFF_AVG_NB A-V differences to make the average */
#define AUDIO_DIFF_AVG_NB   20

/* polls for possible required screen refresh at least this often, should be less than 1/fps */
#define REFRESH_RATE 0.01

/* NOTE: the size must be big enough to compensate the hardware audio buffersize size */
/* TODO: We assume that a decoded and resampled frame fits into this buffer */
#define SAMPLE_ARRAY_SIZE (8 * 65536)

#define CURSOR_HIDE_DELAY 1000000

static int64_t sws_flags = SWS_BICUBIC;

typedef struct MyAVPacketList {
    AVPacket pkt;
    struct MyAVPacketList *next;
    int serial;
} MyAVPacketList;

typedef struct PacketQueue {
    MyAVPacketList *first_pkt, *last_pkt;
    int nb_packets;
    int size;
    int abort_request;
    int serial;
    SDL_mutex *mutex;
    SDL_cond *cond;
} PacketQueue;

#define VIDEO_PICTURE_QUEUE_SIZE 3
#define SUBPICTURE_QUEUE_SIZE 16
#define SAMPLE_QUEUE_SIZE 9
#define FRAME_QUEUE_SIZE FFMAX(SAMPLE_QUEUE_SIZE, FFMAX(VIDEO_PICTURE_QUEUE_SIZE, SUBPICTURE_QUEUE_SIZE))

typedef struct AudioParams {
    int freq;
    int channels;
    int64_t channel_layout;
    enum AVSampleFormat fmt;
    int frame_size;
    int bytes_per_sec;
} AudioParams;

typedef struct Clock {
    double pts;           /* clock base */
    double pts_drift;     /* clock base minus time at which we updated the clock */
    double last_updated;
    double speed;
    int serial;           /* clock is based on a packet with this serial */
    int paused;
    int *queue_serial;    /* pointer to the current packet queue serial, used for obsolete clock detection */
} Clock;

/* Common struct for handling all types of decoded data and allocated render buffers. */
typedef struct Frame {
    AVFrame *frame;
    AVSubtitle sub;
    int serial;
    double pts;           /* presentation timestamp for the frame */
    double duration;      /* estimated duration of the frame */
    int64_t pos;          /* byte position of the frame in the input file */
    SDL_Overlay *bmp;
    int allocated;
    int reallocate;
    int width;
    int height;
    AVRational sar;
} Frame;

typedef struct FrameQueue {
    Frame queue[FRAME_QUEUE_SIZE];
    int rindex;
    int windex;
    int size;
    int max_size;
    int keep_last;
    int rindex_shown;
    SDL_mutex *mutex;
    SDL_cond *cond;
    PacketQueue *pktq;
} FrameQueue;

enum {
    AV_SYNC_AUDIO_MASTER, /* default choice */
    AV_SYNC_VIDEO_MASTER,
    AV_SYNC_EXTERNAL_CLOCK, /* synchronize to an external clock */
};

typedef struct Decoder {
    AVPacket pkt;
    AVPacket pkt_temp;
    PacketQueue *queue;
    AVCodecContext *avctx;
    int pkt_serial;
    int finished;
    int packet_pending;
    SDL_cond *empty_queue_cond;
    int64_t start_pts;
    AVRational start_pts_tb;
    int64_t next_pts;
    AVRational next_pts_tb;
    SDL_Thread *decoder_tid;
} Decoder;

typedef struct VideoState {
    SDL_Thread *read_tid;
    AVInputFormat *iformat;
    int abort_request;
    int force_refresh;
    int paused;
    int last_paused;
    int queue_attachments_req;
    int seek_req;
    int seek_flags;
    int64_t seek_pos;
    int64_t seek_rel;
    int read_pause_return;
    AVFormatContext *ic;
    int realtime;

    Clock audclk;
    Clock vidclk;
    Clock extclk;

    FrameQueue pictq;
    FrameQueue subpq;
    FrameQueue sampq;

    Decoder auddec;
    Decoder viddec;
    Decoder subdec;

    int audio_stream;

    int av_sync_type;

    double audio_clock;
    int audio_clock_serial;
    double audio_diff_cum; /* used for AV difference average computation */
    double audio_diff_avg_coef;
    double audio_diff_threshold;
    int audio_diff_avg_count;
    AVStream *audio_st;
    PacketQueue audioq;
    int audio_hw_buf_size;
    uint8_t silence_buf[SDL_AUDIO_MIN_BUFFER_SIZE];
    uint8_t *audio_buf;
    uint8_t *audio_buf1;
    unsigned int audio_buf_size; /* in bytes */
    unsigned int audio_buf1_size;
    int audio_buf_index; /* in bytes */
    int audio_write_buf_size;
    struct AudioParams audio_src;
#if CONFIG_AVFILTER
    struct AudioParams audio_filter_src;
#endif
    struct AudioParams audio_tgt;
    struct SwrContext *swr_ctx;
    int frame_drops_early;
    int frame_drops_late;

    enum ShowMode {
        SHOW_MODE_NONE = -1, SHOW_MODE_VIDEO = 0, SHOW_MODE_WAVES, SHOW_MODE_RDFT, SHOW_MODE_NB
    } show_mode;
    int16_t sample_array[SAMPLE_ARRAY_SIZE];
    int sample_array_index;
    int last_i_start;
    RDFTContext *rdft;
    int rdft_bits;
    FFTSample *rdft_data;
    int xpos;
    double last_vis_time;

    int subtitle_stream;
    AVStream *subtitle_st;
    PacketQueue subtitleq;

    double frame_timer;
    double frame_last_returned_time;
    double frame_last_filter_delay;
    int video_stream;
    AVStream *video_st;
    PacketQueue videoq;
    double max_frame_duration;      // maximum duration of a frame - above this, we consider the jump a timestamp discontinuity
#if !CONFIG_AVFILTER
    struct SwsContext *img_convert_ctx;
#endif
    SDL_Rect last_display_rect;
    int eof;

    char filename[1024];
    int width, height, xleft, ytop;
    int step;

#if CONFIG_AVFILTER
    int vfilter_idx;
    AVFilterContext *in_video_filter;   // the first filter in the video chain
    AVFilterContext *out_video_filter;  // the last filter in the video chain
    AVFilterContext *in_audio_filter;   // the first filter in the audio chain
    AVFilterContext *out_audio_filter;  // the last filter in the audio chain
    AVFilterGraph *agraph;              // audio filter graph
#endif

    int last_video_stream, last_audio_stream, last_subtitle_stream;

    SDL_cond *continue_read_thread;
} VideoState;

/* options specified by the user */
static AVInputFormat *file_iformat;
static const char *input_filename;
static const char *window_title;
static int fs_screen_width;
static int fs_screen_height;
static int default_width  = 640;
static int default_height = 480;
static int screen_width  = 0;
static int screen_height = 0;
static int audio_disable;
static int video_disable;
static int subtitle_disable;
static const char* wanted_stream_spec[AVMEDIA_TYPE_NB] = {0};
static int seek_by_bytes = -1;
static int display_disable;
static int show_status = 1;
static int av_sync_type = AV_SYNC_AUDIO_MASTER;
static int64_t start_time = AV_NOPTS_VALUE;
static int64_t duration = AV_NOPTS_VALUE;
static int fast = 0;
static int genpts = 0;
static int lowres = 0;
static int decoder_reorder_pts = -1;
static int autoexit;
static int exit_on_keydown;
static int exit_on_mousedown;
static int loop = 1;
static int framedrop = -1;
static int infinite_buffer = -1;
static enum ShowMode show_mode = SHOW_MODE_NONE;
static const char *audio_codec_name;
static const char *subtitle_codec_name;
static const char *video_codec_name;
double rdftspeed = 0.02;
static int64_t cursor_last_shown;
static int cursor_hidden = 0;
#if CONFIG_AVFILTER
static const char **vfilters_list = NULL;
static int nb_vfilters = 0;
static char *afilters = NULL;
#endif
static int autorotate = 1;

/* current context */
static int is_full_screen;
static int64_t audio_callback_time;

static AVPacket flush_pkt;

#define FF_ALLOC_EVENT   (SDL_USEREVENT)
#define FF_QUIT_EVENT    (SDL_USEREVENT + 2)

static SDL_Surface *screen;

#if CONFIG_AVFILTER
static int opt_add_vfilter(void *optctx, const char *opt, const char *arg)
{
    GROW_ARRAY(vfilters_list, nb_vfilters);
    vfilters_list[nb_vfilters - 1] = arg;
    return 0;
}
#endif

static inline
int cmp_audio_fmts(enum AVSampleFormat fmt1, int64_t channel_count1,
                   enum AVSampleFormat fmt2, int64_t channel_count2)
{
    /* If channel count == 1, planar and non-planar formats are the same */
    if (channel_count1 == 1 && channel_count2 == 1)
        return av_get_packed_sample_fmt(fmt1) != av_get_packed_sample_fmt(fmt2);
    else
        return channel_count1 != channel_count2 || fmt1 != fmt2;
}

static inline
int64_t get_valid_channel_layout(int64_t channel_layout, int channels)
{
    if (channel_layout && av_get_channel_layout_nb_channels(channel_layout) == channels)
        return channel_layout;
    else
        return 0;
}

static void free_picture(Frame *vp);

static int packet_queue_put_private(PacketQueue *q, AVPacket *pkt)
{
    MyAVPacketList *pkt1;

    if (q->abort_request)
       return -1;

    pkt1 = av_malloc(sizeof(MyAVPacketList));
    if (!pkt1)
        return -1;
    pkt1->pkt = *pkt;
    pkt1->next = NULL;
    if (pkt == &flush_pkt)
        q->serial++;
    pkt1->serial = q->serial;

    if (!q->last_pkt)
        q->first_pkt = pkt1;
    else
        q->last_pkt->next = pkt1;
    q->last_pkt = pkt1;
    q->nb_packets++;
    q->size += pkt1->pkt.size + sizeof(*pkt1);
    /* XXX: should duplicate packet data in DV case */
    SDL_CondSignal(q->cond);
    return 0;
}

static int packet_queue_put(PacketQueue *q, AVPacket *pkt)
{
    int ret;

    /* duplicate the packet */
    if (pkt != &flush_pkt && av_dup_packet(pkt) < 0)
        return -1;

    SDL_LockMutex(q->mutex);
    ret = packet_queue_put_private(q, pkt);
    SDL_UnlockMutex(q->mutex);

    if (pkt != &flush_pkt && ret < 0)
        av_free_packet(pkt);

    return ret;
}

static int packet_queue_put_nullpacket(PacketQueue *q, int stream_index)
{
    AVPacket pkt1, *pkt = &pkt1;
    av_init_packet(pkt);
    pkt->data = NULL;
    pkt->size = 0;
    pkt->stream_index = stream_index;
    return packet_queue_put(q, pkt);
}

/* packet queue handling */
static void packet_queue_init(PacketQueue *q)
{
    memset(q, 0, sizeof(PacketQueue));
    q->mutex = SDL_CreateMutex();
    q->cond = SDL_CreateCond();
    q->abort_request = 1;
}

static void packet_queue_flush(PacketQueue *q)
{
    MyAVPacketList *pkt, *pkt1;

    SDL_LockMutex(q->mutex);
    for (pkt = q->first_pkt; pkt; pkt = pkt1) {
        pkt1 = pkt->next;
        av_free_packet(&pkt->pkt);
        av_freep(&pkt);
    }
    q->last_pkt = NULL;
    q->first_pkt = NULL;
    q->nb_packets = 0;
    q->size = 0;
    SDL_UnlockMutex(q->mutex);
}

static void packet_queue_destroy(PacketQueue *q)
{
    packet_queue_flush(q);
    SDL_DestroyMutex(q->mutex);
    SDL_DestroyCond(q->cond);
}

static void packet_queue_abort(PacketQueue *q)
{
    SDL_LockMutex(q->mutex);

    q->abort_request = 1;

    SDL_CondSignal(q->cond);

    SDL_UnlockMutex(q->mutex);
}

static void packet_queue_start(PacketQueue *q)
{
    SDL_LockMutex(q->mutex);
    q->abort_request = 0;
    packet_queue_put_private(q, &flush_pkt);
    SDL_UnlockMutex(q->mutex);
}

/* return < 0 if aborted, 0 if no packet and > 0 if packet.  */
static int packet_queue_get(PacketQueue *q, AVPacket *pkt, int block, int *serial)
{
    MyAVPacketList *pkt1;
    int ret;

    SDL_LockMutex(q->mutex);

    for (;;) {
        if (q->abort_request) {
            ret = -1;
            break;
        }

        pkt1 = q->first_pkt;
        if (pkt1) {
            q->first_pkt = pkt1->next;
            if (!q->first_pkt)
                q->last_pkt = NULL;
            q->nb_packets--;
            q->size -= pkt1->pkt.size + sizeof(*pkt1);
            *pkt = pkt1->pkt;
            if (serial)
                *serial = pkt1->serial;
            av_free(pkt1);
            ret = 1;
            break;
        } else if (!block) {
            ret = 0;
            break;
        } else {
            SDL_CondWait(q->cond, q->mutex);
        }
    }
    SDL_UnlockMutex(q->mutex);
    return ret;
}

static void decoder_init(Decoder *d, AVCodecContext *avctx, PacketQueue *queue, SDL_cond *empty_queue_cond) {
    memset(d, 0, sizeof(Decoder));
    d->avctx = avctx;
    d->queue = queue;
    d->empty_queue_cond = empty_queue_cond;
    d->start_pts = AV_NOPTS_VALUE;
}

static int decoder_decode_frame(Decoder *d, AVFrame *frame, AVSubtitle *sub) {
    int got_frame = 0;

    do {
        int ret = -1;

        if (d->queue->abort_request)
            return -1;

        if (!d->packet_pending || d->queue->serial != d->pkt_serial) {
            AVPacket pkt;
            do {
                if (d->queue->nb_packets == 0)
                    SDL_CondSignal(d->empty_queue_cond);
                if (packet_queue_get(d->queue, &pkt, 1, &d->pkt_serial) < 0)
                    return -1;
                if (pkt.data == flush_pkt.data) {
                    avcodec_flush_buffers(d->avctx);
                    d->finished = 0;
                    d->next_pts = d->start_pts;
                    d->next_pts_tb = d->start_pts_tb;
                }
            } while (pkt.data == flush_pkt.data || d->queue->serial != d->pkt_serial);
            av_free_packet(&d->pkt);
            d->pkt_temp = d->pkt = pkt;
            d->packet_pending = 1;
        }

        switch (d->avctx->codec_type) {
            case AVMEDIA_TYPE_VIDEO:
                ret = avcodec_decode_video2(d->avctx, frame, &got_frame, &d->pkt_temp);
                if (got_frame) {
                    if (decoder_reorder_pts == -1) {
                        frame->pts = av_frame_get_best_effort_timestamp(frame);
                    } else if (decoder_reorder_pts) {
                        frame->pts = frame->pkt_pts;
                    } else {
                        frame->pts = frame->pkt_dts;
                    }
                }
                break;
            case AVMEDIA_TYPE_AUDIO:
                ret = avcodec_decode_audio4(d->avctx, frame, &got_frame, &d->pkt_temp);
                if (got_frame) {
                    AVRational tb = (AVRational){1, frame->sample_rate};
                    if (frame->pts != AV_NOPTS_VALUE)
                        frame->pts = av_rescale_q(frame->pts, d->avctx->time_base, tb);
                    else if (frame->pkt_pts != AV_NOPTS_VALUE)
                        frame->pts = av_rescale_q(frame->pkt_pts, av_codec_get_pkt_timebase(d->avctx), tb);
                    else if (d->next_pts != AV_NOPTS_VALUE)
                        frame->pts = av_rescale_q(d->next_pts, d->next_pts_tb, tb);
                    if (frame->pts != AV_NOPTS_VALUE) {
                        d->next_pts = frame->pts + frame->nb_samples;
                        d->next_pts_tb = tb;
                    }
                }
                break;
            case AVMEDIA_TYPE_SUBTITLE:
                ret = avcodec_decode_subtitle2(d->avctx, sub, &got_frame, &d->pkt_temp);
                break;
        }

        if (ret < 0) {
            d->packet_pending = 0;
        } else {
            d->pkt_temp.dts =
            d->pkt_temp.pts = AV_NOPTS_VALUE;
            if (d->pkt_temp.data) {
                if (d->avctx->codec_type != AVMEDIA_TYPE_AUDIO)
                    ret = d->pkt_temp.size;
                d->pkt_temp.data += ret;
                d->pkt_temp.size -= ret;
                if (d->pkt_temp.size <= 0)
                    d->packet_pending = 0;
            } else {
                if (!got_frame) {
                    d->packet_pending = 0;
                    d->finished = d->pkt_serial;
                }
            }
        }
    } while (!got_frame && !d->finished);

    return got_frame;
}

static void decoder_destroy(Decoder *d) {
    av_free_packet(&d->pkt);
}

static void frame_queue_unref_item(Frame *vp)
{
    av_frame_unref(vp->frame);
    avsubtitle_free(&vp->sub);
}

static int frame_queue_init(FrameQueue *f, PacketQueue *pktq, int max_size, int keep_last)
{
    int i;
    memset(f, 0, sizeof(FrameQueue));
    if (!(f->mutex = SDL_CreateMutex()))
        return AVERROR(ENOMEM);
    if (!(f->cond = SDL_CreateCond()))
        return AVERROR(ENOMEM);
    f->pktq = pktq;
    f->max_size = FFMIN(max_size, FRAME_QUEUE_SIZE);
    f->keep_last = !!keep_last;
    for (i = 0; i < f->max_size; i++)
        if (!(f->queue[i].frame = av_frame_alloc()))
            return AVERROR(ENOMEM);
    return 0;
}

static void frame_queue_destory(FrameQueue *f)
{
    int i;
    for (i = 0; i < f->max_size; i++) {
        Frame *vp = &f->queue[i];
        frame_queue_unref_item(vp);
        av_frame_free(&vp->frame);
        free_picture(vp);
    }
    SDL_DestroyMutex(f->mutex);
    SDL_DestroyCond(f->cond);
}

static void frame_queue_signal(FrameQueue *f)
{
    SDL_LockMutex(f->mutex);
    SDL_CondSignal(f->cond);
    SDL_UnlockMutex(f->mutex);
}

static Frame *frame_queue_peek(FrameQueue *f)
{
    return &f->queue[(f->rindex + f->rindex_shown) % f->max_size];
}

static Frame *frame_queue_peek_next(FrameQueue *f)
{
    return &f->queue[(f->rindex + f->rindex_shown + 1) % f->max_size];
}

static Frame *frame_queue_peek_last(FrameQueue *f)
{
    return &f->queue[f->rindex];
}

static Frame *frame_queue_peek_writable(FrameQueue *f)
{
    /* wait until we have space to put a new frame */
    SDL_LockMutex(f->mutex);
    while (f->size >= f->max_size &&
           !f->pktq->abort_request) {
        SDL_CondWait(f->cond, f->mutex);
    }
    SDL_UnlockMutex(f->mutex);

    if (f->pktq->abort_request)
        return NULL;

    return &f->queue[f->windex];
}

static Frame *frame_queue_peek_readable(FrameQueue *f)
{
    /* wait until we have a readable a new frame */
    SDL_LockMutex(f->mutex);
    while (f->size - f->rindex_shown <= 0 &&
           !f->pktq->abort_request) {
        SDL_CondWait(f->cond, f->mutex);
    }
    SDL_UnlockMutex(f->mutex);

    if (f->pktq->abort_request)
        return NULL;

    return &f->queue[(f->rindex + f->rindex_shown) % f->max_size];
}

static void frame_queue_push(FrameQueue *f)
{
    if (++f->windex == f->max_size)
        f->windex = 0;
    SDL_LockMutex(f->mutex);
    f->size++;
    SDL_CondSignal(f->cond);
    SDL_UnlockMutex(f->mutex);
}

static void frame_queue_next(FrameQueue *f)
{
    if (f->keep_last && !f->rindex_shown) {
        f->rindex_shown = 1;
        return;
    }
    frame_queue_unref_item(&f->queue[f->rindex]);
    if (++f->rindex == f->max_size)
        f->rindex = 0;
    SDL_LockMutex(f->mutex);
    f->size--;
    SDL_CondSignal(f->cond);
    SDL_UnlockMutex(f->mutex);
}

/* jump back to the previous frame if available by resetting rindex_shown */
static int frame_queue_prev(FrameQueue *f)
{
    int ret = f->rindex_shown;
    f->rindex_shown = 0;
    return ret;
}

/* return the number of undisplayed frames in the queue */
static int frame_queue_nb_remaining(FrameQueue *f)
{
    return f->size - f->rindex_shown;
}

/* return last shown position */
static int64_t frame_queue_last_pos(FrameQueue *f)
{
    Frame *fp = &f->queue[f->rindex];
    if (f->rindex_shown && fp->serial == f->pktq->serial)
        return fp->pos;
    else
        return -1;
}

static void decoder_abort(Decoder *d, FrameQueue *fq)
{
    packet_queue_abort(d->queue);
    frame_queue_signal(fq);
    SDL_WaitThread(d->decoder_tid, NULL);
    d->decoder_tid = NULL;
    packet_queue_flush(d->queue);
}

static inline void fill_rectangle(SDL_Surface *screen,
                                  int x, int y, int w, int h, int color, int update)
{
    SDL_Rect rect;
    rect.x = x;
    rect.y = y;
    rect.w = w;
    rect.h = h;
    SDL_FillRect(screen, &rect, color);
    if (update && w > 0 && h > 0)
        SDL_UpdateRect(screen, x, y, w, h);
}

/* draw only the border of a rectangle */
static void fill_border(int xleft, int ytop, int width, int height, int x, int y, int w, int h, int color, int update)
{
    int w1, w2, h1, h2;

    /* fill the background */
    w1 = x;
    if (w1 < 0)
        w1 = 0;
    w2 = width - (x + w);
    if (w2 < 0)
        w2 = 0;
    h1 = y;
    if (h1 < 0)
        h1 = 0;
    h2 = height - (y + h);
    if (h2 < 0)
        h2 = 0;
    fill_rectangle(screen,
                   xleft, ytop,
                   w1, height,
                   color, update);
    fill_rectangle(screen,
                   xleft + width - w2, ytop,
                   w2, height,
                   color, update);
    fill_rectangle(screen,
                   xleft + w1, ytop,
                   width - w1 - w2, h1,
                   color, update);
    fill_rectangle(screen,
                   xleft + w1, ytop + height - h2,
                   width - w1 - w2, h2,
                   color, update);
}

#define ALPHA_BLEND(a, oldp, newp, s)\
((((oldp << s) * (255 - (a))) + (newp * (a))) / (255 << s))

#define RGBA_IN(r, g, b, a, s)\
{\
    unsigned int v = ((const uint32_t *)(s))[0];\
    a = (v >> 24) & 0xff;\
    r = (v >> 16) & 0xff;\
    g = (v >> 8) & 0xff;\
    b = v & 0xff;\
}

#define YUVA_IN(y, u, v, a, s, pal)\
{\
    unsigned int val = ((const uint32_t *)(pal))[*(const uint8_t*)(s)];\
    a = (val >> 24) & 0xff;\
    y = (val >> 16) & 0xff;\
    u = (val >> 8) & 0xff;\
    v = val & 0xff;\
}

#define YUVA_OUT(d, y, u, v, a)\
{\
    ((uint32_t *)(d))[0] = (a << 24) | (y << 16) | (u << 8) | v;\
}


#define BPP 1

static void blend_subrect(AVPicture *dst, const AVSubtitleRect *rect, int imgw, int imgh)
{
    int wrap, wrap3, width2, skip2;
    int y, u, v, a, u1, v1, a1, w, h;
    uint8_t *lum, *cb, *cr;
    const uint8_t *p;
    const uint32_t *pal;
    int dstx, dsty, dstw, dsth;

    dstw = av_clip(rect->w, 0, imgw);
    dsth = av_clip(rect->h, 0, imgh);
    dstx = av_clip(rect->x, 0, imgw - dstw);
    dsty = av_clip(rect->y, 0, imgh - dsth);
    lum = dst->data[0] + dsty * dst->linesize[0];
    cb  = dst->data[1] + (dsty >> 1) * dst->linesize[1];
    cr  = dst->data[2] + (dsty >> 1) * dst->linesize[2];

    width2 = ((dstw + 1) >> 1) + (dstx & ~dstw & 1);
    skip2 = dstx >> 1;
    wrap = dst->linesize[0];
    wrap3 = rect->pict.linesize[0];
    p = rect->pict.data[0];
    pal = (const uint32_t *)rect->pict.data[1];  /* Now in YCrCb! */

    if (dsty & 1) {
        lum += dstx;
        cb += skip2;
        cr += skip2;

        if (dstx & 1) {
            YUVA_IN(y, u, v, a, p, pal);
            lum[0] = ALPHA_BLEND(a, lum[0], y, 0);
            cb[0] = ALPHA_BLEND(a >> 2, cb[0], u, 0);
            cr[0] = ALPHA_BLEND(a >> 2, cr[0], v, 0);
            cb++;
            cr++;
            lum++;
            p += BPP;
        }
        for (w = dstw - (dstx & 1); w >= 2; w -= 2) {
            YUVA_IN(y, u, v, a, p, pal);
            u1 = u;
            v1 = v;
            a1 = a;
            lum[0] = ALPHA_BLEND(a, lum[0], y, 0);

            YUVA_IN(y, u, v, a, p + BPP, pal);
            u1 += u;
            v1 += v;
            a1 += a;
            lum[1] = ALPHA_BLEND(a, lum[1], y, 0);
            cb[0] = ALPHA_BLEND(a1 >> 2, cb[0], u1, 1);
            cr[0] = ALPHA_BLEND(a1 >> 2, cr[0], v1, 1);
            cb++;
            cr++;
            p += 2 * BPP;
            lum += 2;
        }
        if (w) {
            YUVA_IN(y, u, v, a, p, pal);
            lum[0] = ALPHA_BLEND(a, lum[0], y, 0);
            cb[0] = ALPHA_BLEND(a >> 2, cb[0], u, 0);
            cr[0] = ALPHA_BLEND(a >> 2, cr[0], v, 0);
            p++;
            lum++;
        }
        p += wrap3 - dstw * BPP;
        lum += wrap - dstw - dstx;
        cb += dst->linesize[1] - width2 - skip2;
        cr += dst->linesize[2] - width2 - skip2;
    }
    for (h = dsth - (dsty & 1); h >= 2; h -= 2) {
        lum += dstx;
        cb += skip2;
        cr += skip2;

        if (dstx & 1) {
            YUVA_IN(y, u, v, a, p, pal);
            u1 = u;
            v1 = v;
            a1 = a;
            lum[0] = ALPHA_BLEND(a, lum[0], y, 0);
            p += wrap3;
            lum += wrap;
            YUVA_IN(y, u, v, a, p, pal);
            u1 += u;
            v1 += v;
            a1 += a;
            lum[0] = ALPHA_BLEND(a, lum[0], y, 0);
            cb[0] = ALPHA_BLEND(a1 >> 2, cb[0], u1, 1);
            cr[0] = ALPHA_BLEND(a1 >> 2, cr[0], v1, 1);
            cb++;
            cr++;
            p += -wrap3 + BPP;
            lum += -wrap + 1;
        }
        for (w = dstw - (dstx & 1); w >= 2; w -= 2) {
            YUVA_IN(y, u, v, a, p, pal);
            u1 = u;
            v1 = v;
            a1 = a;
            lum[0] = ALPHA_BLEND(a, lum[0], y, 0);

            YUVA_IN(y, u, v, a, p + BPP, pal);
            u1 += u;
            v1 += v;
            a1 += a;
            lum[1] = ALPHA_BLEND(a, lum[1], y, 0);
            p += wrap3;
            lum += wrap;

            YUVA_IN(y, u, v, a, p, pal);
            u1 += u;
            v1 += v;
            a1 += a;
            lum[0] = ALPHA_BLEND(a, lum[0], y, 0);

            YUVA_IN(y, u, v, a, p + BPP, pal);
            u1 += u;
            v1 += v;
            a1 += a;
            lum[1] = ALPHA_BLEND(a, lum[1], y, 0);

            cb[0] = ALPHA_BLEND(a1 >> 2, cb[0], u1, 2);
            cr[0] = ALPHA_BLEND(a1 >> 2, cr[0], v1, 2);

            cb++;
            cr++;
            p += -wrap3 + 2 * BPP;
            lum += -wrap + 2;
        }
        if (w) {
            YUVA_IN(y, u, v, a, p, pal);
            u1 = u;
            v1 = v;
            a1 = a;
            lum[0] = ALPHA_BLEND(a, lum[0], y, 0);
            p += wrap3;
            lum += wrap;
            YUVA_IN(y, u, v, a, p, pal);
            u1 += u;
            v1 += v;
            a1 += a;
            lum[0] = ALPHA_BLEND(a, lum[0], y, 0);