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使用ffmpeg将mp4转为ts的命令格式如下：
[AppleScript] 纯文本查看 复制代码 ffmpeg -i b.mp4 -codec copy -bsf h264_mp4toannexb a.ts
如果不使用-bsf h264_mp4toannexb参数，会提示错误，错误信息如下：
[AppleScript] 纯文本查看 复制代码 ffmpeg -i b.mp4 -codec copy a.ts
ffmpeg version N-65108-gf2855eb Copyright (c) 2000-2014 the FFmpeg developers
built on Jul 31 2014 02:29:27 with gcc 4.4.7 (GCC) 20120313 (Red Hat 4.4.7-4)
configuration: --prefix=/usr/local --enable-gpl --enable-nonfree --enable-libfaac --enable-libfreetype --enable-libx264 --enable-libx265
libavutil 52. 93.100 / 52. 93.100
libavcodec 55. 71.100 / 55. 71.100
libavformat 55. 49.100 / 55. 49.100
libavdevice 55. 13.102 / 55. 13.102
libavfilter 4. 11.102 / 4. 11.102
libswscale 2. 6.100 / 2. 6.100
libswresample 0. 19.100 / 0. 19.100
libpostproc 52. 3.100 / 52. 3.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'b.mp4':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2avc1mp41
title : bbs.chinaffmpeg.com 孙悟空
encoder : Lavf55.49.100
copyright :bbs.chinaffmpeg.com 孙悟空
Duration: 00:04:09.44, start: 0.000000, bitrate: 568 kb/s
Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 592x336, 436 kb/s, 23.98 fps, 23.98 tbr, 785647.00 tbn, 47.95 tbc (default)
Metadata:
handler_name : VideoHandler
Stream #0:1(und): Audio: aac (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 127 kb/s (default)
Metadata:
handler_name : SoundHandler
File 'a.ts' already exists. Overwrite ? [y/N] y
[adts @ 0x2269660] Using AVStream.codec.time_base as a timebase hint to the muxer is deprecated. Set AVStream.time_base instead.
Output #0, mpegts, to 'a.ts':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2avc1mp41
title : bbs.chinaffmpeg.com 孙悟空
copyright : bbs.chinaffmpeg.com 孙悟空
encoder : Lavf55.49.100
Stream #0:0(und): Video: h264 (avc1 / 0x31637661), yuv420p, 592x336, q=2-31, 436 kb/s, 23.98 fps, 90k tbn, 23.98 tbc (default)
Metadata:
handler_name : VideoHandler
Stream #0:1(und): Audio: aac (mp4a / 0x6134706D), 44100 Hz, stereo, 127 kb/s (default)
Metadata:
handler_name : SoundHandler
Stream mapping:
Stream #0:0 -> #0:0 (copy)
Stream #0:1 -> #0:1 (copy)
Press [q] to stop, [?] for help
[mpegts @ 0x22761a0] H.264 bitstream malformed, no startcode found, use the h264_mp4toannexb bitstream filter (-bsf h264_mp4toannexb)
av_interleaved_write_frame(): Invalid argument
frame= 1 fps=0.0 q=-1.0 Lsize= 1kB time=00:00:00.04 bitrate= 216.3kbits/s
video:1kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
Conversion failed!
从上面的提示纤细可以看到，提示了：
[AppleScript] 纯文本查看 复制代码 [mpegts @ 0x22761a0] H.264 bitstream malformed, no startcode found, use the h264_mp4toannexb bitstream filter (-bsf h264_mp4toannexb)
av_interleaved_write_frame(): Invalid argument
主要是因为使用了mp4中的h264编码，而h264有两种封装：
一种是annexb模式，传统模式，有startcode，SPS和PPS是在ES中；另一种是mp4模式，一般mp4、mkv、avi会没有startcode，SPS和PPS以及其它信息被封装在container中，每一个frame前面是这个frame的长度，很多解码器只支持annexb这种模式，因此需要将mp4做转换；在ffmpeg中用h264_mp4toannexb_filter可以做转换；所以需要使用-bsf h264_mp4toannexb来进行转换；
下面介绍一下代码实现：
代码实现主要分为三个步骤：
[AppleScript] 纯文本查看 复制代码
1. 初始化filterav_bitstream_filter_init
2. 使用filter转换av_bitstream_filter_filter
3. 关闭filter av_bitstream_filter_close
其他与正常的转封装相同
[C] 纯文本查看 复制代码
#include <stdio.h>
#include <stdlib.h>
#include <libavformat/avformat.h>
#include <libavutil/avutil.h>
#define FORMAT "mpegts"
#define OUTPUT_FILE "./fuck.ts"
#define INPUT_FILE "./a.avi"
int main(int argc, char *argv[])
{
AVPacket pkt;
AVFormatContext *input_fmtctx = NULL;
AVFormatContext *output_fmtctx = NULL;
AVCodecContext *enc_ctx = NULL;
AVCodecContext *dec_ctx = NULL;
AVCodec *encoder = NULL;
AVBitStreamFilterContext * vbsf = NULL;
int ret = 0;
int i = 0;
int have_key = 0;
static int first_pkt = 1;
av_register_all();
if (avformat_open_input(&input_fmtctx, INPUT_FILE, NULL, NULL) < 0) {
av_log(NULL, AV_LOG_ERROR, "Cannot open the file %s bbs.chinaffmpeg.com 孙悟空\n", "./a.mp4");
return -ENOENT;
}
if (avformat_find_stream_info(input_fmtctx,0) < 0) {
av_log(NULL, AV_LOG_ERROR, "bbs.chinaffmpeg.com 孙悟空 Failed to retrieve input stream information\n");
return -EINVAL;
}
av_dump_format(input_fmtctx, NULL, INPUT_FILE, 0);
if (avformat_alloc_output_context2(&output_fmtctx, NULL, FORMAT, OUTPUT_FILE) < 0) {
av_log(NULL, AV_LOG_ERROR, "Cannot open the file %s bbs.chinaffmpeg.com 孙悟空 \n", OUTPUT_FILE);
return -ENOENT;
}
/* Process transcode parameters */
for (i = 0; i < input_fmtctx->nb_streams; i++) {
AVStream *out_stream = NULL;
AVStream *in_stream = NULL;
in_stream = input_fmtctx->streams[i];
out_stream = avformat_new_stream(output_fmtctx, in_stream->codec->codec);
if (out_stream < 0) {
av_log(NULL, AV_LOG_ERROR, "bbs.chinaffmpeg.com 孙悟空 Alloc new Stream error\n");
return -EINVAL;
}
avcodec_copy_context(output_fmtctx->streams[i]->codec, input_fmtctx->streams[i]->codec);
out_stream->codec->codec_tag = 0;
if (output_fmtctx->oformat->flags & AVFMT_GLOBALHEADER) {
out_stream->codec->flags |= CODEC_FLAG_GLOBAL_HEADER;
}
}
vbsf = av_bitstream_filter_init("h264_mp4toannexb");
av_dump_format(output_fmtctx, NULL, OUTPUT_FILE, 1);
if (avio_open2(&output_fmtctx->pb, OUTPUT_FILE, AVIO_FLAG_WRITE, &output_fmtctx->interrupt_callback, NULL) < 0) {
av_log(NULL, AV_LOG_ERROR, "cannot open the output file '%s'\n", "./fuck.m3u8");
return -ENOENT;
}
if ((ret = avformat_write_header(output_fmtctx, NULL)) < 0) {
av_log(NULL, AV_LOG_ERROR, "Cannot write the header for the file '%s' ret = %d bbs.chinaffmpeg.com 孙悟空\n", "fuck.ts", ret);
return -ENOENT;
}
while (1) {
AVStream *in_stream = NULL;
AVStream *out_stream = NULL;
ret = av_read_frame(input_fmtctx, &pkt);
if (ret < 0) {
av_log(NULL, AV_LOG_ERROR, "read frame error %d\n", ret);
break;
}
if (pkt.pts == AV_NOPTS_VALUE && first_pkt) {
pkt.pts = pkt.dts;
first_pkt = 0;
}
in_stream = input_fmtctx->streams[pkt.stream_index];
out_stream = output_fmtctx->streams[pkt.stream_index];
pkt.pts = av_rescale_q_rnd(pkt.pts, in_stream->time_base, out_stream->time_base, AV_ROUND_NEAR_INF | AV_ROUND_PASS_MINMAX);
pkt.dts = av_rescale_q_rnd(pkt.dts, in_stream->time_base, out_stream->time_base, AV_ROUND_NEAR_INF | AV_ROUND_PASS_MINMAX);
pkt.duration = av_rescale_q(pkt.duration, in_stream->time_base, out_stream->time_base);
pkt.pos = -1;
if (pkt.stream_index == 0) {
AVPacket fpkt = pkt;
av_bitstream_filter_filter(vbsf,out_stream->codec, NULL, &fpkt.data, &fpkt.size,pkt.data, pkt.size, pkt.flags & AV_PKT_FLAG_KEY);
pkt.data = fpkt.data;
pkt.size = fpkt.size;
}
ret = av_write_frame(output_fmtctx, &pkt);
if (ret < 0) {
av_log(NULL, AV_LOG_ERROR, "bbs.chinaffmpeg.com 孙悟空 Muxing Error\n");
break;
}
av_free_packet(&pkt);
}
av_write_trailer(output_fmtctx);
avformat_close_input(&input_fmtctx);
avio_close(output_fmtctx->pb);
avformat_free_context(output_fmtctx);
av_bitstream_filter_close(vbsf);
vbsf = NULL;
return 0;
}
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发表于 2014-8-22 13:36:32