/* * 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 */ /* shared code for simple demux/decode tools */ #include <stdlib.h>#include <string.h> #include "decode_simple.h" #include "libavformat/avformat.h" #include "libavcodec/avcodec.h"#include "libavcodec/packet.h" #include "libavutil/dict.h"#include "libavutil/error.h"#include "libavutil/frame.h" static int decode_read(DecodeContext *dc, int flush){    const int ret_done = flush ? AVERROR_EOF : AVERROR(EAGAIN);    int ret = 0;     while (ret >= 0 &&           (dc->max_frames == 0 || dc->decoder->frame_number < dc->max_frames)) {        ret = avcodec_receive_frame(dc->decoder, dc->frame);        if (ret < 0) {            if (ret == AVERROR_EOF) {                int err = dc->process_frame(dc, NULL);                if (err < 0)                    return err;            }             return (ret == ret_done) ? 0 : ret;        }         ret = dc->process_frame(dc, dc->frame);        av_frame_unref(dc->frame);        if (ret < 0)            return ret;         if (dc->max_frames && dc->decoder->frame_number == dc->max_frames)            return 1;    }     return (dc->max_frames == 0 || dc->decoder->frame_number < dc->max_frames) ? 0 : 1;} int ds_run(DecodeContext *dc){    int ret;     ret = avcodec_open2(dc->decoder, NULL, &dc->decoder_opts);    if (ret < 0)        return ret;     while (ret >= 0) {        ret = av_read_frame(dc->demuxer, dc->pkt);        if (ret < 0)            goto flush;        if (dc->pkt->stream_index != dc->stream->index) {            av_packet_unref(dc->pkt);            continue;        }         ret = avcodec_send_packet(dc->decoder, dc->pkt);        if (ret < 0) {            fprintf(stderr, "Error decoding: %d\n", ret);            return ret;        }        av_packet_unref(dc->pkt);         ret = decode_read(dc, 0);        if (ret < 0) {            fprintf(stderr, "Error decoding: %d\n", ret);            return ret;        } else if (ret > 0)            return 0;    } flush:    avcodec_send_packet(dc->decoder, NULL);    ret = decode_read(dc, 1);    if (ret < 0) {        fprintf(stderr, "Error flushing: %d\n", ret);        return ret;    }     return 0;} void ds_free(DecodeContext *dc){    av_dict_free(&dc->decoder_opts);     av_frame_free(&dc->frame);    av_packet_free(&dc->pkt);     avcodec_free_context(&dc->decoder);    avformat_close_input(&dc->demuxer);} int ds_open(DecodeContext *dc, const char *url, int stream_idx){    const AVCodec *codec;    int ret;     memset(dc, 0, sizeof(*dc));     dc->pkt   = av_packet_alloc();    dc->frame = av_frame_alloc();    if (!dc->pkt || !dc->frame) {        ret = AVERROR(ENOMEM);        goto fail;    }     ret = avformat_open_input(&dc->demuxer, url, NULL, NULL);    if (ret < 0) {        fprintf(stderr, "Error opening input file: %d\n", ret);        return ret;    }     if (stream_idx < 0 || stream_idx >= dc->demuxer->nb_streams)        return AVERROR(EINVAL);     dc->stream = dc->demuxer->streams[stream_idx];     codec = avcodec_find_decoder(dc->stream->codecpar->codec_id);    if (!codec)        return AVERROR_DECODER_NOT_FOUND;     dc->decoder = avcodec_alloc_context3(codec);    if (!dc->decoder)        return AVERROR(ENOMEM);     return 0; fail:    ds_free(dc);    return ret;}