可能重复：
Segmentation fault
目前我正在升级用于HTTP流的开源程序。它需要支持最新的FFMPEG。 尽管我遇到了分段错误错误，但代码编译时没有任何警告。 我想知道如何解决这个问题？和/或调试的最佳方法？由于尺寸，请查找附上的部分代码。我将尝试将项目添加到github :)提前感谢！
样本用法
# segmenter --i out.ts --l 10 --o stream.m3u8 --d segments --f stream
生成文件
FFLIBS=`pkg-config --libs libavformat libavcodec libavutil`
FFFLAGS=`pkg-config --cflags libavformat libavcodec libavutil`
all:
gcc -Wall -g segmenter.c -o segmenter ${FFFLAGS} ${FFLIBS}
segmenter.c
/*
* Copyright (c) 2009 Chase Douglas
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <math.h>
#include <unistd.h>
#include "libavformat/avformat.h"
#include "libavformat/avio.h"
#include <sys/stat.h>
#include "segmenter.h"
#include "libavformat/avformat.h"
#define IMAGE_ID3_SIZE 9171
void printUsage() {
fprintf(stderr, "\nExample: segmenter --i infile --d baseDir --f baseFileName --o playListFile.m3u8 --l 10 \n");
fprintf(stderr, "\nOptions: \n");
fprintf(stderr, "--i <infile>.\n");
fprintf(stderr, "--o <outfile>.\n");
fprintf(stderr, "--d basedir, the base directory for files.\n");
fprintf(stderr, "--f baseFileName, output files will be baseFileName-#.\n");
fprintf(stderr, "--l segment length, the length of each segment.\n");
fprintf(stderr, "--a, audio only decode for < 64k streams.\n");
fprintf(stderr, "--v, video only decode for < 64k streams.\n");
fprintf(stderr, "--version, print version details and exit.\n");
fprintf(stderr, "\n\n");
}
void ffmpeg_version() {
// output build and version numbers
fprintf(stderr, " libavutil version: %s\n", AV_STRINGIFY(LIBAVUTIL_VERSION));
fprintf(stderr, " libavutil build: %d\n", LIBAVUTIL_BUILD);
fprintf(stderr, " libavcodec version: %s\n", AV_STRINGIFY(LIBAVCODEC_VERSION));
fprintf(stdout, " libavcodec build: %d\n", LIBAVCODEC_BUILD);
fprintf(stderr, " libavformat version: %s\n", AV_STRINGIFY(LIBAVFORMAT_VERSION));
fprintf(stderr, " libavformat build: %d\n", LIBAVFORMAT_BUILD);
fprintf(stderr, " built on " __DATE__ " " __TIME__);
#ifdef __GNUC__
fprintf(stderr, ", gcc: " __VERSION__ "\n");
#else
fprintf(stderr, ", using a non-gcc compiler\n");
#endif
}
static AVStream *add_output_stream(AVFormatContext *output_format_context, AVStream *input_stream) {
AVCodecContext *input_codec_context;
AVCodecContext *output_codec_context;
AVStream *output_stream;
output_stream = avformat_new_stream(output_format_context, 0);
if (!output_stream) {
fprintf(stderr, "Segmenter error: Could not allocate stream\n");
exit(1);
}
input_codec_context = input_stream->codec;
output_codec_context = output_stream->codec;
output_codec_context->codec_id = input_codec_context->codec_id;
output_codec_context->codec_type = input_codec_context->codec_type;
output_codec_context->codec_tag = input_codec_context->codec_tag;
output_codec_context->bit_rate = input_codec_context->bit_rate;
output_codec_context->extradata = input_codec_context->extradata;
output_codec_context->extradata_size = input_codec_context->extradata_size;
if (av_q2d(input_codec_context->time_base) * input_codec_context->ticks_per_frame > av_q2d(input_stream->time_base) && av_q2d(input_stream->time_base) < 1.0 / 1000) {
output_codec_context->time_base = input_codec_context->time_base;
output_codec_context->time_base.num *= input_codec_context->ticks_per_frame;
} else {
output_codec_context->time_base = input_stream->time_base;
}
switch (input_codec_context->codec_type) {
#ifdef USE_OLD_FFMPEG
case CODEC_TYPE_AUDIO:
#else
case AVMEDIA_TYPE_AUDIO:
#endif
output_codec_context->channel_layout = input_codec_context->channel_layout;
output_codec_context->sample_rate = input_codec_context->sample_rate;
output_codec_context->channels = input_codec_context->channels;
output_codec_context->frame_size = input_codec_context->frame_size;
if ((input_codec_context->block_align == 1 && input_codec_context->codec_id == CODEC_ID_MP3) || input_codec_context->codec_id == CODEC_ID_AC3) {
output_codec_context->block_align = 0;
} else {
output_codec_context->block_align = input_codec_context->block_align;
}
break;
#ifdef USE_OLD_FFMPEG
case CODEC_TYPE_VIDEO:
#else
case AVMEDIA_TYPE_VIDEO:
#endif
output_codec_context->pix_fmt = input_codec_context->pix_fmt;
output_codec_context->width = input_codec_context->width;
output_codec_context->height = input_codec_context->height;
output_codec_context->has_b_frames = input_codec_context->has_b_frames;
if (output_format_context->oformat->flags & AVFMT_GLOBALHEADER) {
output_codec_context->flags |= CODEC_FLAG_GLOBAL_HEADER;
}
break;
default:
break;
}
return output_stream;
}
int write_index_file(const char index[], const char tmp_index[], const unsigned int planned_segment_duration, const unsigned int actual_segment_duration[],
const char output_directory[], const char output_prefix[], const char output_file_extension[],
const unsigned int first_segment, const unsigned int last_segment) {
FILE *index_fp;
char *write_buf;
unsigned int i;
index_fp = fopen(tmp_index, "w");
if (!index_fp) {
fprintf(stderr, "Could not open temporary m3u8 index file (%s), no index file will be created\n", tmp_index);
return -1;
}
write_buf = malloc(sizeof (char) * 1024);
if (!write_buf) {
fprintf(stderr, "Could not allocate write buffer for index file, index file will be invalid\n");
fclose(index_fp);
return -1;
}
unsigned int maxDuration = planned_segment_duration;
for (i = first_segment; i <= last_segment; i++)
if (actual_segment_duration[i] > maxDuration)
maxDuration = actual_segment_duration[i];
snprintf(write_buf, 1024, "#EXTM3U\n#EXT-X-TARGETDURATION:%u\n", maxDuration);
if (fwrite(write_buf, strlen(write_buf), 1, index_fp) != 1) {
fprintf(stderr, "Could not write to m3u8 index file, will not continue writing to index file\n");
free(write_buf);
fclose(index_fp);
return -1;
}
for (i = first_segment; i <= last_segment; i++) {
snprintf(write_buf, 1024, "#EXTINF:%u,\n%s-%u%s\n", actual_segment_duration[i], output_prefix, i, output_file_extension);
if (fwrite(write_buf, strlen(write_buf), 1, index_fp) != 1) {
fprintf(stderr, "Could not write to m3u8 index file, will not continue writing to index file\n");
free(write_buf);
fclose(index_fp);
return -1;
}
}
snprintf(write_buf, 1024, "#EXT-X-ENDLIST\n");
if (fwrite(write_buf, strlen(write_buf), 1, index_fp) != 1) {
fprintf(stderr, "Could not write last file and endlist tag to m3u8 index file\n");
free(write_buf);
fclose(index_fp);
return -1;
}
free(write_buf);
fclose(index_fp);
return rename(tmp_index, index);
}
int main(int argc, const char *argv[]) {
//input parameters
char inputFilename[MAX_FILENAME_LENGTH], playlistFilename[MAX_FILENAME_LENGTH], baseDirName[MAX_FILENAME_LENGTH], baseFileName[MAX_FILENAME_LENGTH];
char baseFileExtension[5]; //either "ts", "aac" or "mp3"
int segmentLength, outputStreams, verbosity, version;
char currentOutputFileName[MAX_FILENAME_LENGTH];
char tempPlaylistName[MAX_FILENAME_LENGTH];
//these are used to determine the exact length of the current segment
double prev_segment_time = 0;
double segment_time;
unsigned int actual_segment_durations[2048];
double packet_time = 0;
//new variables to keep track of output size
double output_bytes = 0;
unsigned int output_index = 1;
AVOutputFormat *ofmt;
AVFormatContext *ic = NULL;
AVFormatContext *oc;
AVStream *video_st = NULL;
AVStream *audio_st = NULL;
AVCodec *codec;
int video_index;
int audio_index;
unsigned int first_segment = 1;
unsigned int last_segment = 0;
int write_index = 1;
int decode_done;
int ret;
int i;
unsigned char id3_tag[128];
unsigned char * image_id3_tag;
size_t id3_tag_size = 73;
int newFile = 1; //a boolean value to flag when a new file needs id3 tag info in it
if (parseCommandLine(inputFilename, playlistFilename, baseDirName, baseFileName, baseFileExtension, &outputStreams, &segmentLength, &verbosity, &version, argc, argv) != 0)
return 0;
if (version) {
ffmpeg_version();
return 0;
}
fprintf(stderr, "%s %s\n", playlistFilename, tempPlaylistName);
image_id3_tag = malloc(IMAGE_ID3_SIZE);
if (outputStreams == OUTPUT_STREAM_AUDIO)
build_image_id3_tag(image_id3_tag);
build_id3_tag((char *) id3_tag, id3_tag_size);
snprintf(tempPlaylistName, strlen(playlistFilename) + strlen(baseDirName) + 1, "%s%s", baseDirName, playlistFilename);
strncpy(playlistFilename, tempPlaylistName, strlen(tempPlaylistName));
strncpy(tempPlaylistName, playlistFilename, MAX_FILENAME_LENGTH);
strncat(tempPlaylistName, ".", 1);
//decide if this is an aac file or a mpegts file.
//postpone deciding format until later
/* ifmt = av_find_input_format("mpegts");
if (!ifmt)
{
fprintf(stderr, "Could not find MPEG-TS demuxer.\n");
exit(1);
} */
av_log_set_level(AV_LOG_DEBUG);
av_register_all();
ret = avformat_open_input(&ic, inputFilename, NULL, NULL);
if (ret != 0) {
fprintf(stderr, "Could not open input file %s. Error %d.\n", inputFilename, ret);
exit(1);
}
if (avformat_find_stream_info(ic, NULL) < 0) {
fprintf(stderr, "Could not read stream information.\n");
exit(1);
}
oc = avformat_alloc_context();
if (!oc) {
fprintf(stderr, "Could not allocate output context.");
exit(1);
}
video_index = -1;
audio_index = -1;
for (i = 0; i < ic->nb_streams && (video_index < 0 || audio_index < 0); i++) {
switch (ic->streams[i]->codec->codec_type) {
#ifdef USE_OLD_FFMPEG
case CODEC_TYPE_VIDEO:
#else
case AVMEDIA_TYPE_VIDEO:
#endif
video_index = i;
ic->streams[i]->discard = AVDISCARD_NONE;
if (outputStreams & OUTPUT_STREAM_VIDEO)
video_st = add_output_stream(oc, ic->streams[i]);
break;
#ifdef USE_OLD_FFMPEG
case CODEC_TYPE_AUDIO:
#else
case AVMEDIA_TYPE_AUDIO:
#endif
audio_index = i;
ic->streams[i]->discard = AVDISCARD_NONE;
if (outputStreams & OUTPUT_STREAM_AUDIO)
audio_st = add_output_stream(oc, ic->streams[i]);
break;
default:
ic->streams[i]->discard = AVDISCARD_ALL;
break;
}
}
if (video_index == -1) {
fprintf(stderr, "Stream must have video component.\n");
exit(1);
}
//now that we know the audio and video output streams
//we can decide on an output format.
if (outputStreams == OUTPUT_STREAM_AUDIO) {
//the audio output format should be the same as the audio input format
switch (ic->streams[audio_index]->codec->codec_id) {
case CODEC_ID_MP3:
fprintf(stderr, "Setting output audio to mp3.");
strncpy(baseFileExtension, ".mp3", strlen(".mp3"));
ofmt = av_guess_format("mp3", NULL, NULL);
break;
case CODEC_ID_AAC:
fprintf(stderr, "Setting output audio to aac.");
ofmt = av_guess_format("adts", NULL, NULL);
break;
default:
fprintf(stderr, "Codec id %d not supported.\n", ic->streams[audio_index]->id);
}
if (!ofmt) {
fprintf(stderr, "Could not find audio muxer.\n");
exit(1);
}
} else {
ofmt = av_guess_format("mpegts", NULL, NULL);
if (!ofmt) {
fprintf(stderr, "Could not find MPEG-TS muxer.\n");
exit(1);
}
}
oc->oformat = ofmt;
if (outputStreams & OUTPUT_STREAM_VIDEO && oc->oformat->flags & AVFMT_GLOBALHEADER) {
oc->flags |= CODEC_FLAG_GLOBAL_HEADER;
}
/* Deprecated: pass the options to avformat_write_header directly.
if (av_set_parameters(oc, NULL) < 0) {
fprintf(stderr, "Invalid output format parameters.\n");
exit(1);
}
*/
av_dump_format(oc, 0, baseFileName, 1);
//open the video codec only if there is video data
if (video_index != -1) {
if (outputStreams & OUTPUT_STREAM_VIDEO)
codec = avcodec_find_decoder(video_st->codec->codec_id);
else
codec = avcodec_find_decoder(ic->streams[video_index]->codec->codec_id);
if (!codec) {
fprintf(stderr, "Could not find video decoder, key frames will not be honored.\n");
}
if (outputStreams & OUTPUT_STREAM_VIDEO)
ret = avcodec_open2(video_st->codec, codec, NULL);
else
avcodec_open2(ic->streams[video_index]->codec, codec, NULL);
if (ret < 0) {
fprintf(stderr, "Could not open video decoder, key frames will not be honored.\n");
}
}
snprintf(currentOutputFileName, strlen(baseDirName) + strlen(baseFileName) + strlen(baseFileExtension) + 10, "%s%s-%u%s", baseDirName, baseFileName, output_index++, baseFileExtension);
if (avio_open(&oc->pb, currentOutputFileName, URL_WRONLY) < 0) {
fprintf(stderr, "Could not open '%s'.\n", currentOutputFileName);
exit(1);
}
newFile = 1;
int r = avformat_write_header(oc,NULL);
if (r) {
fprintf(stderr, "Could not write mpegts header to first output file.\n");
debugReturnCode(r);
exit(1);
}
//no segment info is written here. This just creates the shell of the playlist file
write_index = !write_index_file(playlistFilename, tempPlaylistName, segmentLength, actual_segment_durations, baseDirName, baseFileName, baseFileExtension, first_segment, last_segment);
do {
AVPacket packet;
decode_done = av_read_frame(ic, &packet);
if (decode_done < 0) {
break;
}
if (av_dup_packet(&packet) < 0) {
fprintf(stderr, "Could not duplicate packet.");
av_free_packet(&packet);
break;
}
//this time is used to check for a break in the segments
// if (packet.stream_index == video_index && (packet.flags & PKT_FLAG_KEY))
// {
// segment_time = (double)video_st->pts.val * video_st->time_base.num / video_st->time_base.den;
// }
#if USE_OLD_FFMPEG
if (packet.stream_index == video_index && (packet.flags & PKT_FLAG_KEY))
#else
if (packet.stream_index == video_index && (packet.flags & AV_PKT_FLAG_KEY))
#endif
{
segment_time = (double) packet.pts * ic->streams[video_index]->time_base.num / ic->streams[video_index]->time_base.den;
}
// else if (video_index < 0)
// {
// segment_time = (double)audio_st->pts.val * audio_st->time_base.num / audio_st->time_base.den;
// }
//get the most recent packet time
//this time is used when the time for the final segment is printed. It may not be on the edge of
//of a keyframe!
if (packet.stream_index == video_index)
packet_time = (double) packet.pts * ic->streams[video_index]->time_base.num / ic->streams[video_index]->time_base.den; //(double)video_st->pts.val * video_st->time_base.num / video_st->time_base.den;
else if (outputStreams & OUTPUT_STREAM_AUDIO)
packet_time = (double) audio_st->pts.val * audio_st->time_base.num / audio_st->time_base.den;
else
continue;
//start looking for segment splits for videos one half second before segment duration expires. This is because the
//segments are split on key frames so we cannot expect all segments to be split exactly equally.
if (segment_time - prev_segment_time >= segmentLength - 0.5) {
fprintf(stderr, "looking to print index file at time %lf\n", segment_time);
avio_flush(oc->pb);
avio_close(oc->pb);
if (write_index) {
actual_segment_durations[++last_segment] = (unsigned int) rint(segment_time - prev_segment_time);
write_index = !write_index_file(playlistFilename, tempPlaylistName, segmentLength, actual_segment_durations, baseDirName, baseFileName, baseFileExtension, first_segment, last_segment);
fprintf(stderr, "Writing index file at time %lf\n", packet_time);
}
struct stat st;
stat(currentOutputFileName, &st);
output_bytes += st.st_size;
snprintf(currentOutputFileName, strlen(baseDirName) + strlen(baseFileName) + strlen(baseFileExtension) + 10, "%s%s-%u%s", baseDirName, baseFileName, output_index++, baseFileExtension);
if (avio_open(&oc->pb, currentOutputFileName, URL_WRONLY) < 0) {
fprintf(stderr, "Could not open '%s'\n", currentOutputFileName);
break;
}
newFile = 1;
prev_segment_time = segment_time;
}
if (outputStreams == OUTPUT_STREAM_AUDIO && packet.stream_index == audio_index) {
if (newFile && outputStreams == OUTPUT_STREAM_AUDIO) {
//add id3 tag info
//fprintf(stderr, "adding id3tag to file %s\n", currentOutputFileName);
//printf("%lf %lld %lld %lld %lld %lld %lf\n", segment_time, audio_st->pts.val, audio_st->cur_dts, audio_st->cur_pkt.pts, packet.pts, packet.dts, packet.dts * av_q2d(ic->streams[audio_index]->time_base) );
fill_id3_tag((char*) id3_tag, id3_tag_size, packet.dts);
avio_write(oc->pb, id3_tag, id3_tag_size);
avio_write(oc->pb, image_id3_tag, IMAGE_ID3_SIZE);
avio_flush(oc->pb);
newFile = 0;
}
packet.stream_index = 0; //only one stream in audio only segments
ret = av_interleaved_write_frame(oc, &packet);
} else if (outputStreams & OUTPUT_STREAM_VIDEO) {
if (newFile) {
//fprintf(stderr, "New File: %lld %lld %lld\n", packet.pts, video_st->pts.val, audio_st->pts.val);
//printf("%lf %lld %lld %lld %lld %lld %lf\n", segment_time, audio_st->pts.val, audio_st->cur_dts, audio_st->cur_pkt.pts, packet.pts, packet.dts, packet.dts * av_q2d(ic->streams[audio_index]->time_base) );
newFile = 0;
}
if (outputStreams == OUTPUT_STREAM_VIDEO)
ret = av_write_frame(oc, &packet);
else
ret = av_interleaved_write_frame(oc, &packet);
}
if (ret < 0) {
fprintf(stderr, "Warning: Could not write frame of stream.\n");
} else if (ret > 0) {
fprintf(stderr, "End of stream requested.\n");
av_free_packet(&packet);
break;
}
av_free_packet(&packet);
} while (!decode_done);
//make sure all packets are written and then close the last file.
avio_flush(oc->pb);
av_write_trailer(oc);
if (video_st && video_st->codec)
avcodec_close(video_st->codec);
if (audio_st && audio_st->codec)
avcodec_close(audio_st->codec);
for (i = 0; i < oc->nb_streams; i++) {
av_freep(&oc->streams[i]->codec);
av_freep(&oc->streams[i]);
}
avio_close(oc->pb);
av_free(oc);
struct stat st;
stat(currentOutputFileName, &st);
output_bytes += st.st_size;
if (write_index) {
actual_segment_durations[++last_segment] = (unsigned int) rint(packet_time - prev_segment_time);
//make sure that the last segment length is not zero
if (actual_segment_durations[last_segment] == 0)
actual_segment_durations[last_segment] = 1;
write_index_file(playlistFilename, tempPlaylistName, segmentLength, actual_segment_durations, baseDirName, baseFileName, baseFileExtension, first_segment, last_segment);
}
write_stream_size_file(baseDirName, baseFileName, output_bytes * 8 / segment_time);
return 0;
}
答案 0 :(得分：3)
您尝试过哪些基本的调试步骤？您是否在gdb或调试器下运行代码以发现它崩溃的行？或者至少，添加了打印语句，以查看崩溃前程序的进度是多少？
首先在编译器中使用“-g”选项编译源代码，以添加调试符号。然后在gdb下运行你的代码。
valgrind是另一个有用的工具，它可以帮助您找到程序在触及无效内存时崩溃的位置。