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swresample_frame.c 4.36 KiB
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  • /*
     * Copyright (c) 2014 Luca Barbato <lu_zero@gentoo.org>
     * Copyright (c) 2014 Michael Niedermayer <michaelni@gmx.at>
     *
     * 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
     */
    
    #include "swresample_internal.h"
    #include "libavutil/frame.h"
    #include "libavutil/opt.h"
    
    int swr_config_frame(SwrContext *s, const AVFrame *out, const AVFrame *in)
    {
        swr_close(s);
    
        if (in) {
            if (av_opt_set_int(s, "icl", in->channel_layout, 0) < 0)
                goto fail;
            if (av_opt_set_int(s, "isf", in->format, 0) < 0)
                goto fail;
            if (av_opt_set_int(s, "isr", in->sample_rate, 0) < 0)
                goto fail;
        }
    
        if (out) {
            if (av_opt_set_int(s, "ocl", out->channel_layout, 0) < 0)
                goto fail;
            if (av_opt_set_int(s, "osf", out->format,  0) < 0)
                goto fail;
            if (av_opt_set_int(s, "osr", out->sample_rate, 0) < 0)
                goto fail;
        }
    
        return 0;
    fail:
        av_log(s, AV_LOG_ERROR, "Failed to set option\n");
        return AVERROR(EINVAL);
    }
    
    static int config_changed(SwrContext *s,
                              const AVFrame *out, const AVFrame *in)
    {
        int ret = 0;
    
        if (in) {
            if (s->in_ch_layout   != in->channel_layout ||
                s->in_sample_rate != in->sample_rate ||
                s->in_sample_fmt  != in->format) {
                ret |= AVERROR_INPUT_CHANGED;
            }
        }
    
        if (out) {
            if (s->out_ch_layout   != out->channel_layout ||
                s->out_sample_rate != out->sample_rate ||
                s->out_sample_fmt  != out->format) {
                ret |= AVERROR_OUTPUT_CHANGED;
            }
        }
    
        return ret;
    }
    
    static inline int convert_frame(SwrContext *s,
                                    AVFrame *out, const AVFrame *in)
    {
        int ret;
        uint8_t **out_data = NULL;
        const uint8_t **in_data = NULL;
        int out_nb_samples = 0, in_nb_samples = 0;
    
        if (out) {
            out_data       = out->extended_data;
            out_nb_samples = out->nb_samples;
        }
    
        if (in) {
            in_data       = (const uint8_t **)in->extended_data;
            in_nb_samples = in->nb_samples;
        }
    
        ret = swr_convert(s, out_data, out_nb_samples, in_data, in_nb_samples);
    
        if (ret < 0) {
            if (out)
                out->nb_samples = 0;
            return ret;
        }
    
        if (out)
            out->nb_samples = ret;
    
        return 0;
    }
    
    static inline int available_samples(AVFrame *out)
    {
        int bytes_per_sample = av_get_bytes_per_sample(out->format);
        int samples = out->linesize[0] / bytes_per_sample;
    
        if (av_sample_fmt_is_planar(out->format)) {
            return samples;
        } else {
            int channels = av_get_channel_layout_nb_channels(out->channel_layout);
            return samples / channels;
        }
    }
    
    int swr_convert_frame(SwrContext *s,
                          AVFrame *out, const AVFrame *in)
    {
        int ret, setup = 0;
    
        if (!swr_is_initialized(s)) {
            if ((ret = swr_config_frame(s, out, in)) < 0)
                return ret;
            if ((ret = swr_init(s)) < 0)
                return ret;
            setup = 1;
        } else {
            // return as is or reconfigure for input changes?
            if ((ret = config_changed(s, out, in)))
                return ret;
        }
    
        if (out) {
            if (!out->linesize[0]) {
                out->nb_samples =   swr_get_delay(s, s->out_sample_rate)
                                  + in->nb_samples*(int64_t)s->out_sample_rate / s->in_sample_rate
                                  + 3;
                if ((ret = av_frame_get_buffer(out, 0)) < 0) {
                    if (setup)
                        swr_close(s);
                    return ret;
                }
            } else {
                if (!out->nb_samples)
                    out->nb_samples = available_samples(out);
            }
        }
    
        return convert_frame(s, out, in);
    }