播放器系列之ffplay源码分析(五)

1、配置filtergraph

static int configure_filtergraph(AVFilterGraph *graph, const char *filtergraph,
                                 AVFilterContext *source_ctx, AVFilterContext *sink_ctx)
{
    int ret, i;
    int nb_filters = graph->nb_filters;
    AVFilterInOut *outputs = NULL, *inputs = NULL;

    if (filtergraph) {
        outputs = avfilter_inout_alloc();
        inputs  = avfilter_inout_alloc();
        if (!outputs || !inputs) {
            ret = AVERROR(ENOMEM);
            goto fail;
        }

        outputs->name       = av_strdup("in");
        outputs->filter_ctx = source_ctx;
        outputs->pad_idx    = 0;
        outputs->next       = NULL;

        inputs->name        = av_strdup("out");
        inputs->filter_ctx  = sink_ctx;
        inputs->pad_idx     = 0;
        inputs->next        = NULL;

        if ((ret = avfilter_graph_parse_ptr(graph, filtergraph, &inputs, &outputs, NULL)) < 0)
            goto fail;
    } else {
        if ((ret = avfilter_link(source_ctx, 0, sink_ctx, 0)) < 0)
            goto fail;
    }

    /* Reorder the filters to ensure that inputs of the custom filters are merged first */
    for (i = 0; i < graph->nb_filters - nb_filters; i++)
        FFSWAP(AVFilterContext*, graph->filters[i], graph->filters[i + nb_filters]);

    ret = avfilter_graph_config(graph, NULL);
fail:
    avfilter_inout_free(&outputs);
    avfilter_inout_free(&inputs);
    return ret;
}

2、根据filtergraph配置视频的filter

static int configure_video_filters(AVFilterGraph *graph, VideoState *is, const char *vfilters, AVFrame *frame)
{
    enum AVPixelFormat pix_fmts[FF_ARRAY_ELEMS(sdl_texture_format_map)];
    char sws_flags_str[512] = "";
    char buffersrc_args[256];
    int ret;
    AVFilterContext *filt_src = NULL, *filt_out = NULL, *last_filter = NULL;
    AVCodecParameters *codecpar = is->video_st->codecpar;
    AVRational fr = av_guess_frame_rate(is->ic, is->video_st, NULL);
    AVDictionaryEntry *e = NULL;
    int nb_pix_fmts = 0;
    int i, j;

    for (i = 0; i < renderer_info.num_texture_formats; i++) {
        for (j = 0; j < FF_ARRAY_ELEMS(sdl_texture_format_map) - 1; j++) {
            if (renderer_info.texture_formats[i] == sdl_texture_format_map[j].texture_fmt) {
                pix_fmts[nb_pix_fmts++] = sdl_texture_format_map[j].format;
                break;
            }
        }
    }
    pix_fmts[nb_pix_fmts] = AV_PIX_FMT_NONE;

    while ((e = av_dict_get(sws_dict, "", e, AV_DICT_IGNORE_SUFFIX))) {
        if (!strcmp(e->key, "sws_flags")) {
            av_strlcatf(sws_flags_str, sizeof(sws_flags_str), "%s=%s:", "flags", e->value);
        } else
            av_strlcatf(sws_flags_str, sizeof(sws_flags_str), "%s=%s:", e->key, e->value);
    }
    if (strlen(sws_flags_str))
        sws_flags_str[strlen(sws_flags_str)-1] = '\0';

    graph->scale_sws_opts = av_strdup(sws_flags_str);

    snprintf(buffersrc_args, sizeof(buffersrc_args),
             "video_size=%dx%d:pix_fmt=%d:time_base=%d/%d:pixel_aspect=%d/%d",
             frame->width, frame->height, frame->format,
             is->video_st->time_base.num, is->video_st->time_base.den,
             codecpar->sample_aspect_ratio.num, FFMAX(codecpar->sample_aspect_ratio.den, 1));
    if (fr.num && fr.den)
        av_strlcatf(buffersrc_args, sizeof(buffersrc_args), ":frame_rate=%d/%d", fr.num, fr.den);

    if ((ret = avfilter_graph_create_filter(&filt_src,
                                            avfilter_get_by_name("buffer"),
                                            "ffplay_buffer", buffersrc_args, NULL,
                                            graph)) < 0)
        goto fail;

    ret = avfilter_graph_create_filter(&filt_out,
                                       avfilter_get_by_name("buffersink"),
                                       "ffplay_buffersink", NULL, NULL, graph);
    if (ret < 0)
        goto fail;

    if ((ret = av_opt_set_int_list(filt_out, "pix_fmts", pix_fmts,  AV_PIX_FMT_NONE, AV_OPT_SEARCH_CHILDREN)) < 0)
        goto fail;

    last_filter = filt_out;

/* Note: this macro adds a filter before the lastly added filter, so the
 * processing order of the filters is in reverse */
#define INSERT_FILT(name, arg) do {                                          \
    AVFilterContext *filt_ctx;                                               \
                                                                             \
    ret = avfilter_graph_create_filter(&filt_ctx,                            \
                                       avfilter_get_by_name(name),           \
                                       "ffplay_" name, arg, NULL, graph);    \
    if (ret < 0)                                                             \
        goto fail;                                                           \
                                                                             \
    ret = avfilter_link(filt_ctx, 0, last_filter, 0);                        \
    if (ret < 0)                                                             \
        goto fail;                                                           \
                                                                             \
    last_filter = filt_ctx;                                                  \
} while (0)

    if (autorotate) {
        double theta  = get_rotation(is->video_st);

        if (fabs(theta - 90) < 1.0) {
            INSERT_FILT("transpose", "clock");
        } else if (fabs(theta - 180) < 1.0) {
            INSERT_FILT("hflip", NULL);
            INSERT_FILT("vflip", NULL);
        } else if (fabs(theta - 270) < 1.0) {
            INSERT_FILT("transpose", "cclock");
        } else if (fabs(theta) > 1.0) {
            char rotate_buf[64];
            snprintf(rotate_buf, sizeof(rotate_buf), "%f*PI/180", theta);
            INSERT_FILT("rotate", rotate_buf);
        }
    }

    if ((ret = configure_filtergraph(graph, vfilters, filt_src, last_filter)) < 0)
        goto fail;

    is->in_video_filter  = filt_src;
    is->out_video_filter = filt_out;

fail:
    return ret;
}

3、根据filtergraph配置音频filter

static int configure_audio_filters(VideoState *is, const char *afilters, int force_output_format)
{
    static const enum AVSampleFormat sample_fmts[] = { AV_SAMPLE_FMT_S16, AV_SAMPLE_FMT_NONE };
    int sample_rates[2] = { 0, -1 };
    int64_t channel_layouts[2] = { 0, -1 };
    int channels[2] = { 0, -1 };
    AVFilterContext *filt_asrc = NULL, *filt_asink = NULL;
    char aresample_swr_opts[512] = "";
    AVDictionaryEntry *e = NULL;
    char asrc_args[256];
    int ret;

    avfilter_graph_free(&is->agraph);
    if (!(is->agraph = avfilter_graph_alloc()))
        return AVERROR(ENOMEM);

    while ((e = av_dict_get(swr_opts, "", e, AV_DICT_IGNORE_SUFFIX)))
        av_strlcatf(aresample_swr_opts, sizeof(aresample_swr_opts), "%s=%s:", e->key, e->value);
    if (strlen(aresample_swr_opts))
        aresample_swr_opts[strlen(aresample_swr_opts)-1] = '\0';
    av_opt_set(is->agraph, "aresample_swr_opts", aresample_swr_opts, 0);

    ret = snprintf(asrc_args, sizeof(asrc_args),
                   "sample_rate=%d:sample_fmt=%s:channels=%d:time_base=%d/%d",
                   is->audio_filter_src.freq, av_get_sample_fmt_name(is->audio_filter_src.fmt),
                   is->audio_filter_src.channels,
                   1, is->audio_filter_src.freq);
    if (is->audio_filter_src.channel_layout)
        snprintf(asrc_args + ret, sizeof(asrc_args) - ret,
                 ":channel_layout=0x%"PRIx64,  is->audio_filter_src.channel_layout);

    ret = avfilter_graph_create_filter(&filt_asrc,
                                       avfilter_get_by_name("abuffer"), "ffplay_abuffer",
                                       asrc_args, NULL, is->agraph);
    if (ret < 0)
        goto end;


    ret = avfilter_graph_create_filter(&filt_asink,
                                       avfilter_get_by_name("abuffersink"), "ffplay_abuffersink",
                                       NULL, NULL, is->agraph);
    if (ret < 0)
        goto end;

    if ((ret = av_opt_set_int_list(filt_asink, "sample_fmts", sample_fmts,  AV_SAMPLE_FMT_NONE, AV_OPT_SEARCH_CHILDREN)) < 0)
        goto end;
    if ((ret = av_opt_set_int(filt_asink, "all_channel_counts", 1, AV_OPT_SEARCH_CHILDREN)) < 0)
        goto end;

    if (force_output_format) {
        channel_layouts[0] = is->audio_tgt.channel_layout;
        channels       [0] = is->audio_tgt.channels;
        sample_rates   [0] = is->audio_tgt.freq;
        if ((ret = av_opt_set_int(filt_asink, "all_channel_counts", 0, AV_OPT_SEARCH_CHILDREN)) < 0)
            goto end;
        if ((ret = av_opt_set_int_list(filt_asink, "channel_layouts", channel_layouts,  -1, AV_OPT_SEARCH_CHILDREN)) < 0)
            goto end;
        if ((ret = av_opt_set_int_list(filt_asink, "channel_counts" , channels       ,  -1, AV_OPT_SEARCH_CHILDREN)) < 0)
            goto end;
        if ((ret = av_opt_set_int_list(filt_asink, "sample_rates"   , sample_rates   ,  -1, AV_OPT_SEARCH_CHILDREN)) < 0)
            goto end;
    }


    if ((ret = configure_filtergraph(is->agraph, afilters, filt_asrc, filt_asink)) < 0)
        goto end;

    is->in_audio_filter  = filt_asrc;
    is->out_audio_filter = filt_asink;

end:
    if (ret < 0)
        avfilter_graph_free(&is->agraph);
    return ret;
}

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转载自blog.csdn.net/tong5956/article/details/81539959