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				| @ -0,0 +1,116 @@ | ||||
| //
 | ||||
| // Created by xu fulong on 2022/5/13.
 | ||||
| //
 | ||||
| 
 | ||||
| #include <cut_video.h> | ||||
| 
 | ||||
| #ifdef __ANDROID__ | ||||
| #include <android/log.h> | ||||
| #define LOGE(FORMAT, ...) __android_log_print(ANDROID_LOG_ERROR, "CutVideo", FORMAT, ##__VA_ARGS__) | ||||
| #else | ||||
| #include <stdio.h> | ||||
| #define LOGE(FORMAT, ...) printf(FORMAT, ##__VA_ARGS__) | ||||
| #endif | ||||
| 
 | ||||
| int CutVideo::open_output_file(AVFormatContext *ifmt_ctx, const char *filename) | ||||
| { | ||||
|     int ret; | ||||
|     avformat_alloc_output_context2(&ofmt_ctx, nullptr, nullptr, filename); | ||||
|     if (!ofmt_ctx) { | ||||
|         LOGE("Could not create output context\n"); | ||||
|         return AVERROR_UNKNOWN; | ||||
|     } | ||||
| 
 | ||||
|     for (int i = 0; i < ifmt_ctx->nb_streams; i++) { | ||||
|         AVStream* in_stream = ifmt_ctx->streams[i]; | ||||
|         AVCodecParameters* codecpar = in_stream->codecpar; | ||||
| 
 | ||||
|         AVCodec* dec = avcodec_find_decoder(codecpar->codec_id); | ||||
|         AVStream* out_stream = avformat_new_stream(ofmt_ctx, dec); | ||||
|         if (!out_stream) { | ||||
|             LOGE("Failed allocating output stream\n"); | ||||
|             ret = AVERROR_UNKNOWN; | ||||
|             return ret; | ||||
|         } | ||||
|         avcodec_parameters_copy(out_stream->codecpar, codecpar); | ||||
|     } | ||||
| 
 | ||||
|     av_dump_format(ofmt_ctx, 0, filename, 1); | ||||
|     if (!(ofmt_ctx->oformat->flags & AVFMT_NOFILE)) { | ||||
|         ret = avio_open(&ofmt_ctx->pb, filename, AVIO_FLAG_WRITE); | ||||
|         if (ret < 0) { | ||||
|             LOGE("Could not open output file %s\n", filename); | ||||
|             return ret; | ||||
|         } | ||||
|     } | ||||
|     /* init muxer, write output file header */ | ||||
|     ret = avformat_write_header(ofmt_ctx, nullptr); | ||||
|     if (ret < 0) { | ||||
|         LOGE("Error occurred when opening output file\n"); | ||||
|         return ret; | ||||
|     } | ||||
| 
 | ||||
|     return 0; | ||||
| } | ||||
| 
 | ||||
| AVPacket* CutVideo::copy_packet(AVFormatContext *ifmt_ctx, AVPacket *packet) { | ||||
|     AVStream* in_stream; | ||||
|     AVStream* out_stream; | ||||
|     auto* pkt = (AVPacket*)av_malloc(sizeof(AVPacket)); | ||||
|     av_new_packet(pkt, 0); | ||||
|     if (0 == av_packet_ref(pkt, packet)) { | ||||
|         in_stream  = ifmt_ctx->streams[pkt->stream_index]; | ||||
|         out_stream = ofmt_ctx->streams[pkt->stream_index]; | ||||
|         // 转换pts与dts
 | ||||
|         pkt->pts = av_rescale_q_rnd(pkt->pts, in_stream->time_base, out_stream->time_base, | ||||
|                                     static_cast<AVRounding>(AV_ROUND_NEAR_INF | | ||||
|                                                             AV_ROUND_PASS_MINMAX)); | ||||
|         pkt->dts = av_rescale_q_rnd(pkt->dts, in_stream->time_base, out_stream->time_base, | ||||
|                                     static_cast<AVRounding>(AV_ROUND_NEAR_INF | | ||||
|                                                             AV_ROUND_PASS_MINMAX)); | ||||
|         pkt->duration = av_rescale_q(pkt->duration, in_stream->time_base, out_stream->time_base); | ||||
|         return pkt; | ||||
|     } | ||||
|     return nullptr; | ||||
| } | ||||
| 
 | ||||
| int CutVideo::write_internal(AVFormatContext *ifmt_ctx, AVPacket *packet) | ||||
| { | ||||
|     int ret; | ||||
|     AVPacket *pkt = copy_packet(ifmt_ctx, packet); | ||||
|     if (pkt == nullptr) { | ||||
|         LOGE("packet is NULL\n"); | ||||
|         return -1; | ||||
|     } | ||||
|     // sub the first timestamp offset
 | ||||
|     pkt->pts = pkt->pts - start_pts; | ||||
|     pkt->dts = pkt->dts - start_dts; | ||||
|     // write packet into file
 | ||||
|     if ((ret = av_interleaved_write_frame(ofmt_ctx, pkt)) < 0) { | ||||
|         LOGE("Error muxing packet\n"); | ||||
|     } | ||||
|     av_packet_unref(pkt); | ||||
|     return ret; | ||||
| } | ||||
| 
 | ||||
| void CutVideo::write_output_file(AVFormatContext *ifmt_ctx, AVPacket *packet) { | ||||
|     int64_t timestamp = packet->pts * av_q2d(ifmt_ctx->streams[packet->stream_index]->time_base); | ||||
|     if (timestamp >= start_time && timestamp < start_time + duration) { | ||||
| //        if (start_pts == 0 && start_dts == 0) {
 | ||||
| //            start_pts = packet->pts;
 | ||||
| //            start_dts = packet->dts;
 | ||||
| //        }
 | ||||
|         LOGE("write frame timestamp=%ld\n", timestamp); | ||||
|         write_internal(ifmt_ctx, packet); | ||||
|     } | ||||
| } | ||||
| 
 | ||||
| void CutVideo::close_output_file() { | ||||
|     if (!ofmt_ctx) | ||||
|         return; | ||||
|     av_write_trailer(ofmt_ctx); | ||||
|     if (!(ofmt_ctx->oformat->flags & AVFMT_NOFILE)) { | ||||
|         avio_close(ofmt_ctx->pb); | ||||
|     } | ||||
|     avformat_free_context(ofmt_ctx); | ||||
| } | ||||
| @ -0,0 +1,39 @@ | ||||
| //
 | ||||
| // Created by xu fulong on 2022/5/13.
 | ||||
| //
 | ||||
| 
 | ||||
| #ifndef CUT_VIDEO_H | ||||
| #define CUT_VIDEO_H | ||||
| 
 | ||||
| #ifdef __cplusplus | ||||
| extern "C" { | ||||
| #endif | ||||
| #include "libavformat/avformat.h" | ||||
| #ifdef __cplusplus | ||||
| } | ||||
| #endif | ||||
| 
 | ||||
| class CutVideo { | ||||
| private: | ||||
| 
 | ||||
|     int64_t start_time = 15; | ||||
|     int64_t duration   = 10; | ||||
| 
 | ||||
|     int64_t start_dts = 0; | ||||
|     int64_t start_pts = 0; | ||||
|     AVFormatContext *ofmt_ctx = nullptr; | ||||
| 
 | ||||
|     AVPacket* copy_packet(AVFormatContext *ifmt_ctx, AVPacket *packet); | ||||
| 
 | ||||
|     int write_internal(AVFormatContext *ifmt_ctx, AVPacket *packet); | ||||
| 
 | ||||
| public: | ||||
| 
 | ||||
|     int open_output_file(AVFormatContext *ifmt_ctx, const char *filename); | ||||
| 
 | ||||
|     void write_output_file(AVFormatContext *ifmt_ctx, AVPacket *packet); | ||||
| 
 | ||||
|     void close_output_file(); | ||||
| }; | ||||
| 
 | ||||
| #endif //CUT_VIDEO_H
 | ||||
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